


§ LIBRARY OF CONGRESS. 

Me// T S 



UMTED STATES l E CA. * 






a« 



COMPLIMENTS OF 

JONES & LAUGHLINS. 






REPORT ON COLD-ROLLED 



IRON AND STEEL 



AS MANUFACTURED BY 



JONES & LAUGHLINS' 



AMERICAN IROTST WORKS, 



PITTSBURGH. 



By ROBEKT H. THURSTON, A. M., 0. E., 

Prof, of Engineering, Stevens Institute of Technology ; Member of 
Am. Society of Ciyil Engineers ; Institute of Mining Engineers ; 
Societe des Ingenieures Civils ; Verein Deutsche Ingenieure ; 
Oesterrichische Ingenieure und Architekten Verein; 
Institution of Engineers and Shipbuilders of Scot- 
land, &c, &c, &c; Associate British Institution 
of Naval Architects ; Fellow of New York 
Academy of Sciences ; Am. Association for 
Advancement of Science, 
etc., etc., etc. 



PITTSBURGH: 

Printed by Stevenson, Foster & Co., No. 48 Fifth Avenue 

1878. 



REPORT ON COLD-ROLLED 



IRON AND STEEL 



AS MANUFACTURED BY 



'JONES & LAUGHLINS, 

AMERICAN IRON WORKS, 

PITTSBURGH. 



By ROBERT H. THURSTON, A. M., C. E., 

Prof, of Engineering, Stevens Institute of Technology ; Member of 
Am. Society of Civil Engineers ; Institute of Mining Engineers ; 
societe des ingenieures clvils ; yerein deutsche ingenieure ; 
Oesterrichische Ingenieure und Architekten Yerein; 
Institution of Engineers and Shipbuilders of Scot- 
land, &c, &c, &c.; Associate British Institution 
of Naval Architects ; Fellow of ISTew York 
Academy of Sciences ; Am. Association for 
Advancement of Science, 
etc., etc., etc. 




PITTSBURGH: 
Printed by Stevenson, Foster & Co., No. 48 Fifth Avenue. 

1878. 



3 



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io-m; 



COLD-ROLLED IRON. 



CONTENTS. 

INTRODUCTION : Earlier Work. 

1. Whipple's Tests of Cold-Rolled Iron. 

2. Fairbairn's Tests and Report. 

3. Wade's Results of Test. 

4. Thurston's Earlier Examination. 

REPORT ON COLD-ROLLED IRON UNDER TENSION. 

1. Materials tested ; Machinery used ; Definitions. 

2. Comparison of Tenacity of Cold-Rolled with Untreated Iron Shafting. 

3. Comparison of Turned Iron, Cold-Rolled and Untreated. 

4. Determination of the Effect of Cold-Rolling upon the Interior of the 

Bar. 
■5. General Deductions and Conclusions. 

(1.) Untreated Iron. 

(2.) Cold-Rolled Iron. 

(3.) Annealed Cold-Rolled Iron. 
6. Tables. 

(1.) Cold-Rolled Iron. 

(2.) Untreated Iron. 

(3.) Iron, Cold-Rolled and Annealed. 

REPORT ON TESTS BY TRANSVERSE STRAIN. 

1. Material ; Machinery used ; Definitions. 

2. Details of Tests of Untreated Iron. 

3. Details of Tests of Cold-Rolled Iron. 

4. Details of Tests of Cold- Rolled and Annealed Iron. 

(Each size similarly treated and described.) 

5. Resume : Deductions. 

- (1.) Hot-Rolled Iron. 
(2.) Cold-Rolled Iron. 
(3.) Cold-Rolled and Annealed Iron. 

6. General Conclusions. 

7. Tables. 

WORKING AND BREAKING LOADS : TABLE. 

REPORT ON TESTS BY TORSION. 

1. Methods and Machinery. 

2. Results of Tests. 

3. Autographic Strain-Diagrams. 

4. Conclusions. 



INTRODUCTION. 



The investigations here reported were undertaken by the under- 
signed at the request of Messrs. Jones & Laughlins, proprietors of 
the American Iron Works, Pittsburgh, in the summer of the year 
1877, and have been continued almost uninterruptedly to date. 
They constitute the most complete research upon the properties of 
any one of the many metals used in engineering construction that 
has yet been made, so far as the knowledge of the writer extends. 
They include tests of finished shafting and round iron from 
2 T 9 ¥ inches in diameter down to f inch, both in tension and by 
transverse strain, and tests in the Autographic Recording Testing 
Machine of iron cut from each grade and size. 

The tests exhibiting the fact that cold-rolling produces a bar of 
more uniform strength from surface to centre than is made by the 
common process of hot-rolling, are as important as the results are 
novel. Later tests which exhibit the fact that the u mild" or "low" 
steels, so-called, are benefited by the process are, if possible, of 
greater value than those of iron, since the use of these mild steels 
— or, more properly, homogeneous irons — seems certain to result in 
time in the exclusion of puddled iron and steel from all engineer- 
ing work. 

These investigations have been made in the Mechanical Labora- 
tory of the Department of Engineering of the Stevens Institute 
of Technology, where one-half of each broken test-piece is re- 
tained. The record books of the Laboratory also contain the 
original records from which the figures here given are taken. 
Both the retained samples and the records can be seen, with the re- 
sults of an immense number of other tests, by any one who chooses 
to examine them. In this work I have been greatly assisted by 
JVIr. J. E. Denton, my principal assistant, who has charge of the 



6 



Laboratory, by Mr. T. F. Koezly, Kecorder, and especially by Mr. 
Edward A. Uehling, the observer especially detailed to assist me 
in this work, to whose intelligence, knowledge and skill I am in- 
debted to an extent which I cannot too fully acknowledge. The 
amount of fine work demanded in making such nice determina- 
tion, and the immense amount of calculation involved in the 
working up of results, can only be understood by the very few 
who have themselves engaged in such research. The accuracy and 
neatness of the plates accompanying these reports are due to the 
skill of Mr. F. T. Thurston, C. E. 

The investigations here reported are not the first which have 
been made. In April of the year 1859 the late Chief Engineer, 
John P. Whipple, U. S. N., an officer of great experience and of 
high standing professionally and socially, for whose ability the 
writer can vouch from personal acquaintance, made a series of ex- 
periments upon "bright" or "polished" (cold-rolled) plate-iron ? 
comparing it with the " natural " or ordinary hot-rolled plate, with 

the following results : 

Philadelphia, April 16, 1859. 
Mr. H. P. King, Philadelphia : 

Dear Sir — In compliance with your request, I have tested the samples 
of " Polished Plate" Iron manufactured by Messrs. Jones & Laughlins 5 
Pittsburgh, Pa., in comparison with others of the same quality of iron in 
the natural state. 



The results are shown in the following table : 




, 




B 

O 


Quality of Iron. 


Sectional Area of 

Sample. 

sq. in. 


tJO 

"v «J 

*!■ 

WrtJa 

.Sen" 

g ° 
•— 

W 

19.125 
22.750 
16.875 
27.000 
13,125 
22.750 
20.750 
21.250 


Breaking Weight 

in lbs. 

per sq. in. 


Increase of strength 

in Polished Iron. 

lbs, 


1 


Polished Plate 


.1824 

.424908 

.17126 

.45152 

.1589 

.424908 

.1844 

.1855 


104.852 
53.541 
93.100 
59.797 
82,600 
53.541 
112,527 
114.555 




1 


Natural Plate | 


51.311 


2 


Bright Plate 




2 


Natural Plate „ 


33.403 


3 


Bright Plate 




3 


Natural Plate 


29,059 


4 


Bright Plate 




5 


Bright Plate 











I am, very tiuly, yours, 

JOHN P. WHIPPLE, 

Chief Engineer U. S. N< 



During the summer of the same year, Mr. Wm. Fairbairn,* 
who was then and up to the time of his death (1874,) the most 
distinguished living authority on the use of iron and steel in en- 
gineering construction, made a series of experiments upon cold- 
rolled metal, reporting the following results : 



EXPERIMENT 1. 

On a bar of "Wrought Iron, in the condition in which it is received from the 

manufacturer, (black.) 

Diameter 1.07 inches Area 0.85873 sq. inches. 



Weights laid on 
in pounds. 



Elongation of a length of 
io inches, in inches. 



Breaking Weight 
per square inch. 



9,186 
46,426 
50,346 



1.30 
2.00 



In Lbs. 



58.628 



In Tons. 



26.173 



Diameter at point of fracture after the experiment, 0.88 in. 

EXPERIMENT 2. 

On a bar similar to the preceding, but Eolled Cold. 
Diameter 1.00 inches : Area 0.7854 sq. inches. 





Weights laid on 
in pounds. 


Elongation of a length 
io inches, in inches. 


of 


Break 

per s 


ing Weight 
cniare inch. 


1 


32,590 
37,630 
42,670 
56,110 
57,535 
60,895 
64,255 


0.01 
0.04 

6.07 

0.08 

Elongating 

rapidly. 


In Lbs. 




In Tons. 


2 






3 






4 






5 






6 

7 


Unbroken. 
81,812 


Unbroken. 
36.533 



At this point the experiment was discontinued. 



*Sir Wm. Fairbairn, Baronet; (1869) F. R. S.; LL. D. 



EXPERIMENT 3. 

On a bar of Iron, Eolled Cold. 
Diameter 1.00 inches Area 0.7854 sq. inches. 





Weights laid on 
in pounds. 


Elongation of a length of 
io inches, in inches. 


Breaking Weight 
per square inch. 


1 


10,750 
10,150 

25,870 
32,590 
49,135 
52,495 
62,575 
69,295 


None. 

0.6 
0.79 


In Lbs. In Tons. 


2 




3 




4 




5 




6 




7 




8 


88,230 39.388 



Diameter after fracture, 0.85. 



EXPERIMENT 4. 

On a bar of similar Iron to the preceding, turned in the lathe. 
Diameter 1.00 inches Area 0.7854 sq. inches 





Weights laid on 
in pounds. 


Elongation of a length of 
io inches, in inches. 


Breaking Weight 
per square inch. 


1 


10,750 
19,150 
27,550 
30,910 
34,270 
37,630 
40,990 
42,670 
44,350 
47,710 


0.15 

0.27 
0.48 
0.80 

90 
2.20 


In Lbs. In Tons. 


2 




3 




4 




5 




6 




7 




8 




9 




10 


60,746 27.119 



Diameter after fracture, 0.80. 



9 



GENERAL SUMMARY OF RESULTS. 



Condition of Bar. ' Breaking Weight Breaking Weight 

of car in lbs. per square inch. 



Strength, the untouch- 
ed Bar being unity. 



In Lbs. In Tons. 

1 Untouched (black) 50,346 58.628 26.173 1.000 

3 Rolled Cold 69,295 88.230 39.388 1.505 

4 Turned 47,710 60.746 27.119 1.036 



J^^lti the above summary, it will be observed that the effect of con- 
solidation by the process of Cold-Rolling is to increase the tensile powers 
of resistance from 26.17 tons per square inch, to 39.38 tons, being in the 
ratio of 1 : 1.5. one-half increase of strength gained by the new process 
of Cold-Rollins. 



WILLIAM FAIRBAIRN. 



Manchester, Aug. 5, 1859. 



Manchester, August 26, 1859. 

Sirs: — In conformity with your request, I carefully inspected your 
machinery for Cold-Rolling and Polishing Bar Iron, and I have no hesita- 
tion in bearing my testimony to its efficiency, and the very perfect manner 
in which the work was accomplished, both as regards the consolidation 
of the metal, by which its tenacity is increased, and the roundness and 
straightness of the bars as they left the machine. 

A similar process applied to boiler and bridge plates would not only give 
greatly increased strength, but would secure a smoothness of finish in their 
manufacture admirably adapted to enhance the value and increase the 
importance of iron as a material of construction. 

I append the results of some of the experiments on Cold-Rolled Iron. 

And remain. Sirs, your obedient servant, 

WILLIAM FAIRBAIRN. 



10 



EXPERIMENTS ON THE INCREASE OF COHESIVE 
STRENGTH IN IRON ROLLED COLD. 













c 










• 


J=^ 












S5 


Condition of Ba 


R. 


Tensile 
per 


Strength 
sq. in. 


Elongation of 
inches, 
in inches. 


Ratio of Sjren 
Black .Bar being 
at i,6oo. 






In Lbs. 


In Tons. 






Black Bar, from Rolls.... 




60,746 

58,628 


27.119 
26.173 


2.20 
2.00 


1.037 


Bar turned down to 1 in. 


diam... 


1.000 


Bar rolled cold to 1 in. di 


am , , 


88,230 


39.388 


0.79 


1.505 



The first bar was broken in the condition in which it came from the 
iron manufacturer ; the second was a similar bar turned in the lathe, and 
the third had been subjected to the process of Cold-Rolling. 

It is obvious that the effect of the consolidation in the last case was to 
increase the strength of the bar in the ratio of 10 to 15. 



Manchester , England. 



WILLIAM FAIRBAIRN 



A year later (November 23, I860,) the late Major Wm. Wade, 
U. S. A., whose experiments and reports on ordnance and ord- 
nance metal have made his name familiar throughout the civilized 
world, and whose conscientious and extraordinarily careful and ac- 
curate methods of work are known to every one who was so fortunate 
as to have been familiar with the veteran and his work, also made 
such a series of tests. His results are here transcribed : 



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12 

Major Wade also determined the specific gravity of the metal, 
and, although working with extreme care and making repeated 
determinations, was unable to detect any increase due to cold- 
rolling — an unexpected result, but one which has been confirmed 
by the recent investigations of the writer. 

Still another set of tests were made at the Twenty-sixth Exhi- 
bition of the Franklin Institute, Philadelphia, the committee 
reporting as follows : 

Extract from Report on the Twenty- sixth Exhibition of American Manu- 
factures, by the Franklin Institute, Philadelphia : 

Patent Cold-Rolled Polished Shafting, Jones & Laughlins, Pittsburgh, Pa. 

Deposited by H. D. King. 

A handsome display of cold-rolled and polished iron of various sizes, 
intended for shafting, piston rods or other purposes where turned iron is 
used ; also, flat sheets, suitable for spade and shovel plates, and samples of 
ovals. This iron cannot fail to recommend itself to all interested in the 
manufacture or use of the metal. Its invention and manufacture yield a 
material possessing a surface nearly as dense as steel, much increased elas- 
ticity, and greater resistance to tensile and torsional strains than the same 
sectional area of iron finished in the ordinary method. The bars are con- 
densed in the finishing process to their centres, as will appear from the 
subjoined experiments, made by Merrick & Sons, at their Southwark 
.Foundry, 

TENSILE STRENGTH. 

Lbs. per sq. in. 

Sample No. 1, inferior quality, broke at 49,510 

Same bar polished and condensed 66,862 

Sample No. 2 broke at 57,350 

Same bar polished and condensed 92,623 

35,273 — increase, .61 
TORSIONAL STRENGTH. 

Sample No. 3, 1 T % diameter ; twisted at a strain of 587J lbs. on a lever 25 
inches long. 

Same bar polished and condensed, 1J diameter; twisted at a strain of 1,000 
lbs. od a lever 25 inches long. Increase, 413J lbs.=.97. 

A First Class Premium. 

Finally, the makers report results of tests made on cold-rolled 
iron finger bars for mowing machines, placed in competition with 
steel, thus : 



13 



COMPARATIVE TEST OF FINGER BARS. 

STATEMENT No. J, 

Of a test made at the American Iron Works, Pittsburgh, Pa., August, 1865, to- 
determine the comparative stiffness and elasticity of Finger Bars made of 
Patent Cold Rolled Iron, and those made of Cast Steel, dimensions of the 
Bars being the same. 



KIND OF BAES. 


Weight applied. 


Deflection. 


Permanent Set. 


Difference. 


Cold Rolled 


Lbs. 
270 
250 

375 
310 

450 
330 

550 

380 


in. 
8 
8 

12 
12 

15 
15 

19 
19 


in. 
1-16 
3-16 

i 

2 

H 
H ■ 

7 


in. 


Cast Steel 


l 


Cold Rolled 


¥ 


Cast Steel 


H 


Cold Rolled 




Cold Rolled 


2 


Cast Steel 


2 1 ! 




^1 6 



Weight taken by Dynamometer.. 

STATEMENT No. 2, 

Of a test made at the Reaper and Mower Works of Walter A. Wood, Hoosick 
Palls, N. Y., October 21, 1865, to determine the comparative stiffness and 
elasticity of Pinger Bars made of Patent Cold-Rolled Iron, and those made 
of Steel, dimensions of the Bars beirg the same. 



KIND OF BAKS. 


Weight applied. 


Deflection. 


Permanent Set. 
in. 


Difference. 




Lbs. 


in. 


in. 


Cold Rolled 




6 

6 






Cast Steel, No. 1 




Cast Steel, No. 2, 




6 










8 
8 


5-16 




Cast Steel, No. 1 


5-16 


Cast Steel, No. 2 




8 


1-16 


1-16 




ft 


10 
10 


1-16 
13-16 




Cast Steel, No. 1 


s. 

4. 




< 


10 


3 

8 


5-1G 


Cold Rolled 


EH 

EH 

o 


12 
12 


4 




Cast Steel, No. 1 


H 


Cast Steel, No. 2 


fc 


12 


i 


» 


Cold Rolled 




14 
14 


i 

4 

H 




Cast Steel, No. 1 


3| 


Cast Steel, No. 2 




14 


2J . 


2| 


Cold Rolled 




16 
16 


4 
°4 




Cast Steel, No. 1 


5 


Cast Steel, No. 2 




16 


4.H 

^8 


8* 



Taken all together, these tests and investigations form a very 
valuable and almost encyclopedic collection of facts for the use of 
the engineer. 



R. H. THURSTON. 



14 



REPORT 



N 



STRENGTH, ELASTICITY, DENSITY AND 
OTHER PROPERTIES 

F 

COLD-ROLLED SHAFTING 

MADE BY THE 

AMERICAN IRON WORKS, PITTSBURGH, PA. 

AND ON THE 

Tfnireaied Iron from vuhich it is made. 

By PEOF. E. H. THURSTON, 

Director of the Mechanical Laboratory Stevens Institute of Technology, 

Hoboken, N. J. t 1877. 



REPORT ON TESTS BY TENSILE STRESS. 

The object of the investigation on which the following is a report 
in detail, was to determine the effect upon iron of the process of 
cold-rolling as practiced at the American Iron Works, Pittsburgh, 
and to compare the results of tests made on iron thus treated, with 
those obtained under exactly the same conditions from tests of 
other samples untreated, but off the same bar and originally of the 
same structure, chemical composition and physical properties, and 
thus to bring out all the characteristic properties in such a manner 
that valid conclusions may be drawn as to whether and to what 
degree, the process of cold-rolling is beneficial or detrimental to 
iron as a material of construction. 

The specimens tested by tension were 53 in number, constituting 
three lots : 

Lot No. 1 — Consisted of thirty-five specimens, of five different 
sizes, and each designated, by a letter as follows : A, 2 T 9 6 inches in 
.diameter; B, 2 T V; 0,1*; D, 1 T V; E, ft ; and A', 2& ; B', 2; 



15 

C, IfV } D', 1 i ncn t aQ d F', f. A to E are the marks and sizes 
of the untreated metal, and A' to E r the sizes to which they were 
reduced by the process of cold-rolling. There were three speci- 
mens of each size untreated, and three of each cold-rolled. There 
was also one specimen cf each size of the annealed cold-rolled 
iron. 

The length of these specimens w 7 as originally 40 inches. They 
were all tested as they came from the rolls, without subsequent 
reduction in the lathe. 

Lot No. 2 — Consisted of six specimens turned down in the 
lathe, from bars originally two inches in diameter, to the sizes A, 
If inches; B, 1J; C, 1. There were two specimens of each size, 
one cold-rolled and the other untreated. 

The length of the reduced part, between shoulders, was 24 
inches. 

Lot No. 3 — Consisted of tw r elve specimens, all turned in the 
lathe from round bars two inches in diameter to the sizes A, | 
inch ; B, f; C, |; D, |; E, f ; F, J- inch in diameter — two 
specimens of each size, the one untreated and the other cold-rolled. 

All these specimens were 8 inches between shoulders. 

Lots 1 and 2 were tested by me at the works of the Keystone 
Bridge Company, at Pittsburgh, Pa. 

The testing machine was of the form known as the u Hydraulic 
Machine/' and consisted simply of a hydraulic cylinder in which 
pressure was obtained by pumps driven from the shafting and 
gauged by a Show and Justice gauge. The machine was designed 
for very heavy work, and was not well calculated to bring out 
slight variations of resistance in the material while under strain. 
The friction of the machine was probably sufficient to cover such 
slight variations. 

There being no device for measuring the elongations, the follow- 
ing expedient was resorted to : a steel scale was secured at one 
end to the specimen by means of a clamp-screw., so as to be about 
equi-distant from the chucks. A mark was made on the bar at 
each end of this scale; these initial lines were thus made exactly 
20 inches apart on the .unstrained specimen. 



16 

The stress was applied gradually and regularly, and as the test- 
piece stretched a scriber was frequently drawn across the bar at the 
free end of the scale, thus marking the extensions due to the suc- 
cessive increments of load. These extensions were afterwards care- 
fully measured, and their amounts are given in the tables, where 
they are placed opposite the corresponding loads.* 

This method of indicating and measuring the extensions is not 
mathematically correct, since the distances between the marks, as 
measured after rupture, do not represent with mathematical accu- 
racy the true elongations. f The error, however, which varies from 

* Where the extensions are not given in the tafres, they were either too small 
to be measured by the instruments available, or the marks were not legible. 

fThe inaccuracy in the measurements referred to above is due to the fact 
that the increments of extension, indicated by the marks, do not correctly 
represent the elongations caused by the corresponding loads, but are too great 
by a variable quantity due to the stretch of the bar caused by the continually 
increasing loads. 

Thus the error decreases with the load, being a maximum for the first in- 
crement and zero for the last. 

The true extensions can be determined in the following manner : 



1 1 I I I i I i m 

abed e f cj h 




B 



Let A B represent a bar ruptured at o; a and k are the initial marks on the 
same, and b to h marks indicating elongations. 

Let ti=a 6, the indicated extension for the first load. 
t i=a c, i{ " " second " 

U=a.d, " " " third " 

t L= an, " " " any " 

T=a k—l (the original length) which is the true extension. 
T 1= the true extension for the first load. 
T 2 = '• " ,c second 1< ad. 

T n= " " " any load. 

T z= the difference between the length of the contracted portion m a and a 
cylinder of the same volume, but equal in diameter to the uniformly reduced 
portion of the bar, and letting /=the original distance between the initial 
marks. 

Then we have : 

T-Tz— Ti 

Ti=t l — Tx J similarly 

T-T z — T 2 
T 2= * 2 — T 2 i and 

T— T z — Tn 
T^dfc-T.-— I 

By aid of these formulas the true extension may be found from the measure- 
ments. Although from scientific points of view such errors cannot be over- 
looked, yet practically they may be neglected. It has, therefore, been considered 
not necessary to make the corrections in the table. 



17 

a maximum in the first increment to zero in the last, is quite too in- 
significant to cause an appreciable change in the strain-diagram 
plotted from the tables, and may be neglected. 

To avoid mistakes which might be caused by a misunderstand- 
ing of terms repeatedly used in this report, and to show how cer- 
tain results given in the tables of comparison were derived, the 
following definitions and explanations will be found useful : 

(1) The " Modulus of Elasticity " is the ratio of the elongation 
to the force which produces it, in a piece of which the length and 
cross-section are each unity. Or, in other words, it is a force such 
as would cause a bar whose length and cross-section are unity to 
double its original length, provided the bar could be stretched so 
far and without change in the ratio of elongation. 

If E denote the Modulus of Elasticity, 

P, the force applied, (which force must not strain the speci- 
men beyond its Elastic Limit,) 
K=the area of cross-section, 
L=the length of the bar, 
tthe length of the extension for the load P. 
Then 

E =K • W 

Now, if K and L are each unity, then 

as indicated by the first definition ; and if l=lu, and K is unity, 
then 

E=P, 
as stated in the second definition. 

In our calculations L and i are in linear, and K in square 
inches. P has always been taken as great as possible, care being 
taken, however, to keep well within the Elastic Limit, i. e. y that 
point at which the extensions cease to bear a constant proportion 
to the load. 

^Wood's Eesistance of Materials, new edition, p. 5, 

2 



18 

(2) "Resilience" is a measure of the capacity of a material to 
resist shock, and its value is equal to the amount of energy ex- 
pended, or the "work" performed, in producing distortion or 
rupture. The " Elastic Resilience " is the energy expended, or 
work performed, in straining a material to its elastic limit, and 
the "Ultimate Resilience" is the energy expended, or work per- 
formed, in breaking it ; it is always equal to the product of the 
average resistance of the material into the distance through which 
that resistance is overcome. 

The Moduli of Resilience, Elastic and Ultimate, are, therefore 
the amounts of work done upon a specimen of material whose 
length and cross-section are both unity, to produce the above effects 
respectively. 

To obtain a measure of this quantity : 

Let W denote the Modulus of Ultimate Resilience, 

Pm=the mean force necessary to rupture the specimen, and 
K, L, l=the same as in formula (1), 

Then we have 

Wx ml 
=KL ( 2 ) 

If K and L are both unity, then 

W=Pm/=the number of units of work, as defined in this 
case, inch-pounds, or by taking L and I in feet, we have foot- 
pounds; in the following discussion and in the annexed tables 
the latter will be used, it being the more common unit of work. 

In the appended curves, representing graphically the behavior 
of the several specimens under stress, one inch on the vertical scale 
represents 10,000 pounds of stress per square inch of cross-section, 
and one inch on the horizontal scale, 2.5 per cent, of extension. 

^ The Moduli of Resilience were calculated from these strain- 
diagrams by means of a formula derived in the following manner : 

Let A=the area of the curve in square inches, 
C=the total stretch in per cent., 
0=the mean ordinate of the curve, in inches, 
S=the extreme abscissa, 
Tm=l 0,000 0=mean stress. 



19 

Then 

7rr=S, and 
2.0 

*=2.6±=0, but 

10,000 0=P ; „ . • . P w =25,000^ 
Now, since 

CP 

W^yT^ by definition, we have 

substituting this value of P m above, we have for the Ultimate 
Resilience or shock -resisting power : 

W=250A 
similarly for the Elastic Resilience, or power of resisting a blow 
without permanent change of form : 

W'=250A' 
A 7 being the area of the curve up to the Elastic Limit. 

To determine the Modulus of Elasticity with scientific accuracy 
in specimens of such limited dimensions as those here reported up- 
on, it is necessary to measure the elongations within the Elastic 
Limit to within one-thousandth (0.001) of an inch. But with the 
means of measurement available where these specimens were tested, 
such precise determinations could not be made. For the Moduli 
of Elasticity, therefore, as well as the Moduli of Elastic Resilience 
and for the true extensions, reference must be made to the results 
reported in the tests of the specimens comprising Lot No. 3, which 
were tested in the Mechanical Laboratory of the Stevens Institute 
of Technology. 



20 



COMPARISON OF COLD-ROLLED 



WITH 



UNTREATED IRON SHAFTING 



Discussion of Results Obtained from Tests of 
Specimei2s Comprising Lots Nos. 1 and 2. 

Lot No. 1 . 

No. 1133. Specimen No. 1133 was 40 inches long and 2 T 7 g- 
inches in diameter, rolled cold from a bar 2 T 9 g- inches in diameter ; 
it was placed in the machine and a gradually increasing stress ap- 
plied, its amount being noted at intervals when the extensions were 
marked as given in the appended record sheet. The curve No. 
1133, on Plate No. 1, shows the behavior of this specimen while 
under stress. It passed its Elastic Limit under a load of 59,450 
pounds per square inch of cross-section, and broke with a stress of 
302,400 pounds, giving it a Modulus of Rupture of 64,800 pounds. 
Its total extension was only 1.15 per cent. The fracture was some- 
what granular; the area at the fracture was reduced to 96.14 per 
cent, of the original ; its Modulus of Ultimate Resilience is 600 
foot-pounds and its Modulus of Rupture per unit of area of frac- 
tured section is 67,400 pounds. 

No. 1134. Specimen No. 1134 was of the same dimensions and 
was rolled cold from the same bar as the preceding ; it was tested 
in the same manner. (See record sheet and curve No. 1134, Plate 
I.) This specimen passed its Elastic Limit under a stress of 59,- 
450 pounds per square inch of cross-section, and after extending 
2.75 per cent, it broke under a load of 310,200 pounds, giving it 
a Modulus of Rupture by tension of 66,500 pounds. The frac- 
ture was quite granular. The. area at the point of fracture was re- 



21 

duced to 91.38 per cent, of the original ; the Modulus of Ultimate 
Resilience is 1,672 foot-pounds, and the Modulus of Rupture per 
square inch of fractured section is 72,700 pounds. 

No. 1 135. Specimen No. 1135 was of the same dimensions and 
was treated in the same manner as the two preceding specimens. 
The stress was noted and the extensions marked, as shown in the 
record of tests of this bar; curve No. 1135 graphically represents 
its behavior under stress. This specimen did not pass its Elastic 
Limit until the stress had reached 62,000 pounds per square inch 
of cross-section, after which it extended quite rapidly until it 
broke at a load of 312,700 pounds, giving it a Modulus of Rup- 
ture of 67,000 pounds. The total extension was 4.35 per cent., 
and the fractured area was reduced to 89.05 per cent, of the origi- 
nal. The Modulus of Ultimate Rsilience is 2,770 foot-pounds. 
The fracture was very similar in appearance to the two preceding 
specimens, and the Modulus per square inch of fractured section is 
75,300 pounds. 

No. 1136. Specimen No. 1136 was of untreated common iron; 
it was 40 inches in length and 2re inches in diameter, and was 
tested in the same manner as the preceding specimen, (see record 
sheet and curve No. 1136, Plate I.) This specimen passed its 
Elastic Limit under a stress of 29,800 pounds per square inch of 
cross-section, after which it extended with some irregularity, and 
finally broke under a load of 239,500 pounds, giving a Modulus 
of Rupture of 46,900 pounds. Rupture took place outside of the 
initial marks, hence the total extension could not be accurately 
ascertained ; the part of the bar between the initial marks had ex- 
tended 20.55 per cent. The section at the fracture was reduced 
to 68.45 per cent, of the original section ; the fracture was quite 
rough and lamellar, and showed a slightly granular structure. 
The Modulus of Resilience, due to the above extension, is 8,777 
foot-pounds. The Modulus of Rupture per unit of area of frac- 
tured section is 67.800 pounds. 

No. 1 137. Specimen No. 1137 was a bar of untreated iron of 
the same dimensions as the preceding; it was tested in the same 
manner, and the results tabulated as before, (see record sheet for 
No. 1137 and curve of the same number, Plate I.) This specimen 
passed its Elastic Limit under a stress of 26,200 pounds per square 



22 

inch of cross-section, after which it extended regularly and quite 
rapidly, finally breaking under a load of 239,500 pounds, thus 
giving a Modulus of Rupture of 46,900 pounds. The total ex- 
tension was 26.25 per cent., and the Modulus of Ultimate Resil- 
ience is 11,081 foot-pounds. The section of fracture was reduced 
to 62.15 per cent, of the original, and the Modulus of Rupture 
per unit of fractured area is 74,700 pounds. The fracture was 
quite rough, almost ragged, and showed a granular structure quite 
plainly. 

No. 1 138. Specimen No. 1138 was of untreated iron of the 
same dimensions'as the two preceding specimens ; it was tested in 
the same manner. The Elastic Limit was passed under a stress 
of 29,800 pounds per square inch of cross- section, and it finally 
broke under a load of 329,400 pounds, which gives a Modulus of 
Rupture in tension of 46,400 pounds. It broke outside of the 
initial marks, between which the extension was 18.20 per cent. 
The Modulus of Resilience for that extension is 7,710 foot-pounds. 
The fractured area was 67.91 per cent, of the original section, and 
the Modulus of Rupture per square inch of fractured area is 68 r 
500. The fracture is rough and lamellar, and plainly shows a 
granular structure. 

No. 1139. Specimen No. 1139 was 40 inches long and 2t^ 
inches in diameter ; it was cold-rolled from a bar 2xe inches, and 
was afterwards annealed and tested in the usual manner. (See 
records of tests of 1139 and curve No. 1139, Plate I.) Its Elastic 
Limit was passed under a stress of 31,400 pounds per square inch 
of cross- section, and broke under a load of 216,116 pounds, thus 
having a Modulus of Rupture of 46,300 pounds. It broke outside 
of the scale, having extended 14.25 per cent, between the initial 
marks. The Modulus of Resilience for that extension is 6,076 
foot-pounds. The fracture was quite rough, and showed some signs 
of granular structure. The fractured area was 61.20 per cent, of 
the original. The Modulus of Rupture per square inch of frac- 
tured area is 75,400 pounds. 

No. 1 140. Specimen No. 1140 was 40 inches in length and 2 
inches in diameter. It was cold-rolled from a bar 2tV inches in 
diameter, and was tested in the same manner as the specimens 
already described. The extensions for the successive loads were 



23 

marked as shown in the appended record of test, and a graphical 
representation of the behavior of the specimen under stress is given 
by the curve No. 1140, Plate II, 

This specimen passed its Elastic Limit under a stress of £7,500 
pounds per square inch of cross-section, after which it extended 
regularly and rapidly, and broke under a load of 20S,500 pounds, 
giving it a Modulus of Rupture of 66,400 pounds. It broke out- 
side of the scale, the extension between the initial marks being 
5.60 per cent.; the section at the fracture was reduced to 72.26 per 
cent, of the original area. The fracture, although generally rough 
and fibrous, showed a slightly granular structure in some places. 
The Modulus of Resilience for the measurable extension is 3,107 
foot-pounds, and the Modulus of Rupture per square inch of the 
fractured section is 91,800 pounds. 

No. 1 141. Specimen No. 1141 was of the same dimensions 
and cold-rolled from the same bar as No. 1140 ; it was tested in 
the same way. This bar was placed in the machine twice, giving 
way under a load of 211,100 pounds the first time, and sustaining 
213,650 pounds before it broke at the second trial. Rupture oc- 
curred outside the scale each time, and the marks were not legible ; 
no curve could therefore be plotted. The Modulus of Rupture is 
67,200 pounds, and the Modulus of Rupture per square inch o± 
fractured section is 83,500 pounds. The section at the fracture 
was reduced to 80.22 per cent, of the original section ; the fracture 
was laminated and somewhat granular. The Elastic Limit, the 
Modulus of Resilience and the extension could not be determined. 

No. 1142. Specimen No. 1142 was of the same dimensions as 
No. 1141, and was treated and tested in precisely the same way. 
It passed its Elastic Limit under a load of 57,500 pounds per 
square inch of cross-section, after which it extended rapidly and 
regularly over 11.00 per cent., and finally broke outside of the 
scale under a stress of 211,100 pounds, thus having a Modulus of 
Rupture of 67,200 pounds. The Modulus of Resilience, deter- 
mined from the extension between the initial marks, is 7,136 foot- 
pounds. The area of cross- section of fracture was 73.22 per cent, 
of the original ; the Modulus of Rupture per square inch of frac- 
tured section is 91,900 pounds. The fracture was rough and lam- 
inated and showed a slightly granular structure. 



24 

No. 1143. Specimen No. 1143 was of untreated iron, 2tV inches 
in diameter, and of the same length as all the preceding ; it was 
tested in the same way. (Consult the appended record of test and 
curve No. 1143, Plate II.) This specimen passed its Elastic 
Limit under a stress of 28,200 pounds per square inch of cross- 
section, then extended regularly and rapidly until it broke under a 
load of 162,200 pounds, having elongated 19.25 per cent. The 
Modulus of Rupture is, therefore, 48,500 pounds, and the Modu- 
lus of Ultimate Eesilience is 8,232 foot-pounds. The area of the 
cross-section at fracture was reduced to 70.37 per cent, of the 
original. The fracture was quite rough, almost ragged, somewhat 
laminated, and finely fibrous in structure thoughout. The Modu- 
lus of Rupture per square inch of fractured section is 69,000 
pounds. 

No. 1 144. Specimen No. 1144 was untreated iron, of similar 
dimensions with the preceding; the extensions were marked in the 
same manner. (See appended record sheets and curve No. 1144, 
Plate No. I.) Its Elastic Limit was passed under a load of 28,200 
pounds per square inch of cross-section, but extended 28.75 per 
cent, before it broke, under a load of 163,400 pounds, which gives 
it a Modulus of Rupture of 48,900 pounds. The Modulus of Ul- 
timate Resilience is 12,717 foot-pounds, and that of Rupture per 
unit of fractured section is 81,300 pounds. The area of the frac- 
tured section was reduced to 60.20 per cent, of the original; this 
fracture was rough but not ragged, and generally finely fibrous. 

No. 1 145. Specimen No. 1145 was in all respects like the two 
preceding. This specimen was placed in the machine twice, break- 
ing unfairly each time ; it broke under a load of 160,880 pounds 
on the first test, and sustained 177,650 pounds at the second trial. 
It was reduced from its original diameter, 2rV inches, to lit inches 
in diameter by the first test, and showed an increased strength with 
the reduced diameter. It broke in the jaws of the clamp at the 
second trial. The extensions could not be read. The Modulus of 
Rupture in the first test was 48,100 pounds. The fracture was quite 
rough and somewhat granular. 

No. 1 146. Specimen No. 1146 was 2 inches in diameter and of 
the standard length. It had been cold-rolled from a bar 2tV 
inches in diameter to the above size, and was subsequently an- 



25 

nealed. It passed its Elastic Limit under a stress of 31,800 pounds 
per square iuch of cross-section, after which it extended regularly 
and more and more rapidly, as is shown by the curve No. 1146, 
Plate II, and finally broke under a load of 154,400 pounds, thus 
giving a Modulus of Rupture of 49,600 pounds. Rupture took 
place outside the scale. The extension between the initial marks 
was 12.50 per cent.; the Modulus of Resilience due to that elonga- 
tion is 5,619 foot-pounds. The Modulus of Rupture per unit of 
area of fractured section is 78,400, and the area at the point of frac- 
ture was reduced to 63.22 per cent, of the original dimension. The 
fracture was rough, and very completely fibrous. 

No. 1 147. Specimen No. 1147 was of the standard length and 
ItV inches in diameter. It was cold-rolled from a bar of untreated 
iron If inches in diameter. (See appended record of test and curve 
No. 1147, Plate III.) This specimen passed its Elastic Limit 
under a load of 56,200 pounds per square inch, which is a com- 
paratively low figure; it then elongated very gradually until the 
stress had reached 64,500 pounds per square inch, after which it 
yielded more rapidly, and bi\>ke under a load of 91,400 pounds, 
having extended 5.85 per cent. The Modulus of Rupture in ten- 
sion is 67,500 pounds, and the Modulus of Ultimate Resilience is 
3 616 foot-pounds. The fractured section was reduced to 76.79 
per cent, of the original, and the Modulus of Rupture per unit 
area of fractured section is 87,900 pounds. The fracture was rough, 
and completely and finely fibrous. 

No. 1 148. Specimen No. 1148 was in every respect like the 
preceding, and was tested in the same manner. It passed its 
Elastic Limit under a stress of 60,000 pounds per square inch of 
cross-section. After the load had been increased to 64,500 pounds 
per square inch it elongated very rapidly, and finally broke, after 
elongating 7.35 per cent., under a load of 91,400 pounds, which 
gives it a Modulus of Rupture of 67,500 pounds, and a Modulus 
of Ultimate Resilience of 4,710 foot-pounds. The area at the 
fracture was reduced to 70.22 per cent, of the original cross-sec- 
tion ; the Modulus of Rupture per square inch of fractured area is 
96,200 pounds. The fracture was quite rough, but not ragged, 
and was completely and finely fibrous. 

No. 1149, Specimen No. 1149 was in all respects like the two 



26 

preceding specimens ; it was tested in the same manner. Its Elas- 
tic Limit was passed under a load of 56,200 pounds, the same as 
that of No. 1147, after which it elongated more rapidly than the 
latter, as is seen by studying the curves of No. 1147 and No. 
1149, Plate III; it broke under a load of 92,700 pounds, thus 
giving a Modulus of Rupture of 68,500 pounds. Rupture took 
place outside the scale, the extension between the initial marks 
being 4.90 per cent., and the Modulus of Resilience due to this 
extension is 2,913 foot-pounds. The area of cross-section at the 
fracture was reduced to 82.19 per cent, of the original ; the Modulus 
of Rupture per square inch of fractured area is 83,300 pounds. 
The fracture is rough and generally fibrous, showing traces of gran- 
ular structure. 

No. 1150. Specimen No. 1150 was of the same length as the 
preceding specimens ; it was cut from a bar of common iron If 
inches in diameter, and Avas not cold-rolled. It was tested in the 
usual manner, and the elongations marked as before. It passed its 
Elastic Limit under a stress of 24,300 pounds per square inch of 
cross-section, after which it extended rapidly, and finally broke 
outside of the scale under a load of 74,600 pounds, which gives it 
a Modulus of Rupture of 50,300 pounds. The extension between 
the initial marks was 22.00 per cent., and the Modulus of Resil- 
ience due to that extension is 92.72 foot-pounds. The area of the 
section at fracture was reduced to 60.37 per cent, of the original ; 
the Modulus of Rupture per square inch of fractured section is 
83,000 pounds. The fracture was quite rough and slightly lami- 
nated, and completely fibrous. 

No. 1 1 51. Specimen No. 1151 was in every respect like the 
preceding, and tested in the same manner. It passed its 
Elastic Limit under a load of 24,300 pounds per square inch 
of cross-section, then extended regularly and rapidly until 
it broke under a load of 74,600 pounds, giving a Modulus 
of Rupture of 50,300 pounds. Rupture occurred outside the scale, 
the elongation between the initial marks being 15.65 per cent;; 
the Modulus of Resilience due to that extension is 6,497 foot- 
pounds. The area of section at the fracture was reduced to 62.81 
per cent, of the original ; the Modulus of Rupture per unit ot 
area of fractured section is 80,000 pounds. The fracture was 



27 

rough and laminated, showing a fine fibre with traces of a crystaline 
structure. 

No. 1 152. Specimen No. 1152 was like the preceding speci- 
mens, and it was tested in the same way. (See appended record of 
test and curve of No. 1152, Plate III.) This specimen passed its 
Elastic Limit under the same load as the other two, 24,300 pounds 
per square inch of cross-section, after which it elongated quite 
regularly until it finally gave way under a load of 74,600 pounds, 
giving as a Modulus of Rupture 50,300, which is the same as the 
two preceding specimens. Rupture took place outside the scale, 
the elongation between the initial marks being 22.60 per cent.; the 
Modulus of Resilience due to that extension is 10,141 foot-pounds. 
The area at the fractured section was reduced to 61.69 per cent, of 
the original ; the Modulus of Rupture per square inch of fractured 
section is 81,500 pounds. The fracture was rough, and finely 
fibrous. 

No. 1 153. Specimen No. 1153 was of the standard length, 
and was lxe inches in diameter; cold-rolled from an untreated bar 
If inches in diameter, but it was annealed before testing. It 
passed its Elastic Limit under a stress of 31,600 pounds per square 
inch of cross-section, after which it extended with some irregularity 
(see curve of No. 1153, Plate III), and finally broke under a 
load of 65,400 pounds, having extended 9.50 per cent. The 
Modulus of Rupture is therefore 49,500 pounds, and the Modulus 
of Ultimate Resilience is 4,927 foot-pounds. The area of cross- 
section at the fracture was reduced to 56.91 per cent, of the original 
cross-secticn, and the Modulus of Rupture per square inch of 
fractured section is 86,900 pounds. The fracture was dark, rough 
and fibrous. 

No. 1154. Specimen No. 1154 was of the standard length, and 
was cold-rolled to a diameter of 1 inch from a bar of untreated 
iron ItV inches in diameter; it was tested in the usual manner. 
It passed its Elastic Limit under a stress of 58,700 pounds per 
square inch of cross-section (see curve of No. 1154, Plate IV,) and 
broke after extending 8.05 per cent., under a load of 53,300 pounds, 
thus giving it a Modulus of Rupture of 67,800 pounds, and its 
Modulus of Ultimate Resilience is 5,164 foot-pounds. The area of 
section at rupture was reduced to 67.23 per cent, of the original, 



28 

and the Modulus of Rupture per square inch of fractured section is 
100,900 pounds. The fracture was rough and fibrous. 

No. 1 155. Specimen No. 1155 was in every respect the same 
as the preceding, and was tested in the same manner. It passed its 
Elastic Limit under a stress of 63,700 pounds per square inch of 
oross-section, after which it extended very rapidly (see curve of No. 
1155, Plate IV) ; after it had extended a little over 2 per cent, the 
maximum load, 53,800 pounds, was applied, under which it 
■elongated until it broke. The Modulus of Rupture was 68,500 
pounds. Rupture occurred outside the scale; the elongations be- 
tween the initial marks was 7.45 per cent., and the Modulus of 
Resilience due to that extension is 4,909 foot-pounds. The area of 
section at the fracture was reduced to 67.23 per cent, of the original, 
and the Modulus of Rupture per square inch of fractured section 
is 101,900 pounds. The fracture showed nothing peculiar. 

No. 1 156. Specimen No. 1156 was of standard length, of the same 
diameter as Nos. 1154 and 1155, and was tested in the same manner. 
It passed its Elastic Limit under a stress of 58,700 pounds per 
square inch of cross-section, after which it elongated pretty rapidly 
under an increasing resistance until it broke under a load of 58,500 
pounds, having a Modulus of Rupture of 68,200. Rupture took 
place outside the scale ; the extension between the initial marks was 
5.30 per cent. , and the Modulus of Resilience due to that extension 
is 3,360 foot-pounds. The area of section at the fracture was re- 
duced to 67.23 per cent, of the original, which is the same amount 
as was noted with the two preceding specimens. The Modulus of 
Rupture per unit of fractured section is 101,400 pounds. The 
fracture was like those of the two preceding specimens. 

No. 1 157. Specimen No. 1157 was of standard length and 
Its- inches in diameter. It was common iron and was tested in 
the usual way. This specimen passed its Elastic Limit under a 
load of 26,100 pounds per square inch of cross-section and finally 
broke outside the scale under a load of 42,000 pounds, which gives 
it a Modulus of Rupture of 47,300 pounds. The extension be- 
tween the initial marks is 21.75 per cent., and the Modulus of 
Resilience due to that extension is 7,946 foot- pounds. The area of 
section at the fracture was reduced to 58.09 per cent, of the orig- 
inal area ; the Modulus of Rupture per square inch of fractured 



29 

section is 81,500 pounds. The fracture was rough but not ragged, 
and perfectly fibrous in its structure; several partial fractures ap- 
peared in the reduced portion of the specimen as though it had had 
an equal tendency to break in either of several places. 

No. 1158. Specimen No. 1158 was similar in all respects to- 
the preceding, and was tested in the same manner. It passed its 
Elastic Limit under a stress of 28,900 pounds per square inch of 
cross-section, after which it extended with considerable regularity, 
but with a much higher resistance than its two companion speci- 
mens* (see curves, Plate IV) ; its ultimate resistance is, however,, 
only equal to one of them and less than the other. The Modulus 
of Rupture is 47,300 pounds. Rupture took place outside the 
scale, the elongation between the initial marks being 23.60 per 
cent. ; the Modulus of Resilience due to this extension is 9,882 
foot-pounds. The area of the section at the fracture was reduced 
to 61.03 per cent, of the original area; the Modulus of Rupture 
per square inch of fractured section is 77,600 pounds. The frac- 
ture was quite rough, almost ragged, and exhibited a fibrous 
structure. 

No. 1159. Specimen No. 1159 was like the two preceding spe- 
cimens and was similarly tested. It passed its Elastic Limit under 
a stress of 28,100 pounds per square inch of cross-section and 
finally broke outside the scale under a load of 42.200 pounds, hav- 
ing a Modulus of Resistance of 47,600 pounds. The extension 
between the initial marks was 25.30 per cent., and the Modulus 
of Resilience due to that extension is 9,718 foot-pounds. The 
area of section at fracture was reduced to 59.55 per cent, of its 
original measure ; the Modulus of Rupture per unit of fractured 
area is 79,900 pounds. The fracture was the same as that of the 
preceding specimen. 

No. 1 160. Specimen No. 1160 was 1 inch in diameter, cold- 
rolled from a bar l^g inches in diameter ; it was annealed before 
testing. It passed its Elastic Limit under a load of 32,700 
pounds per square inch of cross-section, after which it extended 

* In the curves Ncs. 1157 and 1159, exhibiting the behavior of these speci- 
mens, we have only one observation between the Elastic Limit and point of 
rupture ; they may therefore not correctly represent the resistances of these 
specimens, although the initial part of the curve shows a weaker metal in both 
cases. 



30 

somewhat irregularly (see curve of 1160, Plate IV), and finally 
broke under a load of 39,900 pounds after extending 12.65 per 
cent. The Modulus of Rupture is 50,900 pounds and the Modu- 
lus of Ultimate Resilience is 5,857 foot-pounds. The area of the 
section at the fracture was reduced to 67.23 per cent, of the orig- 
inal area ; the Modulus of Rupture per square inch of fractured 
section is 75,600 pounds. The fracture exhibited no peculiarities, 
but was finely grained and fibrous. 

No. u6i. Specimen No. 1161 was § inch in diameter; it was 
cold-rolled from a bar of common iron -~| inch in diameter. 
It passed its Elastic Limit under a stress of 63,800 pounds per 
square inch of cross-section, after which it elongated more and more 
rapidly (see curve of No. 1161, Plate V), until it broke under a 
load of 22,600 pounds ; the total extension being 4.85 per cent. 
The Modulus is 73,800 pounds per square inch, which is very 
much higher than was given by any of the preceding sizes. The 
Modulus of Ultimate Resilience is 3,566 foot-pounds. The area 
of section at the fracture is reduced to 69.10 per cent, of the orig- 
inal section ; the Modulus of Rupture per square inch of fractured 
area is 106,800 pounds. The fracture was slightly ragged and 
showed signs of a granular structure. 

No. 1162. Specimen No. 1162 was of the same dimensions 
and materials as the preceding, and was tested in the same manner. 
It passed its Elastic Limit under a load of 67,100 pounds, after 
which it extended very rapidly, and broke under a stress of 22,136 
pounds, giving a Modulus of 72,200 pounds. The total extension 
was 3.75 per cent., and the Modulus of Ultimate Resilience is 
2,657 foot-pounds. The area of cross-section at the fracture was 
reduced to 80.19 per cent, of the original, and the Modulus of 
Rupture per square inch of fractured section is 92,000 pounds. 
The fracture had the same appearance as that of the preceding 
specimen. 

No. 1 163. Specimen No. 1163, which was in all respects like 
the two preceding specimens, passed its Elastic Limit under a 
stress of 60,600 pounds per square inch of cross-section, having 
elongated 5.00 per cent. The Modulus of »Rupture is 75,500 
pounds, and the Modulus of Ultimate Resilience is 3,670 foot- 
pounds. The area of section at the fracture was reduced to 72.01 



31 

per cent, of the original ; the Modulus of Rupture per unit of 
fractured area is 104,800 pounds. The fracture was rough and 
almost entirely fibrous. 

No. i j 64. Specimen No. 1164 was |f inch in diameter and of 
untreated iron. It passed its Elastic Limit under a stress of 29,- 
200 pounds per square inch of cross- section, after which it elon- 
gated very gradually at first until the load was increased to 39,000 
pounds per square inch ; it then yielded quite rapidly, (see curve 
of No. 1164, Plate V,) and finally broke under a load of 17,800 
pounds, thus giving a Modulus of Rupture of 50,100 pounds. 
Rupture occurred outside the scale ; the extension between the 
initial marks was 16.55 per cent., and the Modulus of Resilience 
clue to that extension is 8,001 foot-pounds. The area of the frac- 
tured section was reduced to 69.39 per cent, of the original ; the 
Modulus of Rupture per unit of fractured section is 72,200 pounds. 
The fracture was rough and fibrous. 

No. 1 165. Specimen No. 1165 was similar to the preceding, 
and was tested in the same manner. It passed its Elastic Limit 
under a stress of 29,200 pounds per square inch of cross-section, 
after which it extended under an increasing load with some regu- 
larity until its maximum resistance of 43,600 pounds per square 
inch was reached, with an extension of 7.35 per cent., (see curve of 
No. 1165, Plate V,) under which load it finally gave way, having 
elongated 19.35 per cent. The Modulus of Rupture of this speci- 
men is only 43.600 pounds — much lower than either of its com- 
panion specimens ; the Modulus of Ultimate Resilience is 8,761 
foot-pounds. The area of cross-section at the fracture was reduced 
to 62.34 per cent, of its original section ; the Modulus of Rupture 
per unit of fractured section is 60.900 pounds. The fracture was 
fibrous and slightly ragged. 

No. 1 166. Specimen No. 1166 was like the two preceding 
specimens, and was tested in the same way. It passed the Elastic 
Limit under a stress of 29,200 pounds per square inch of cross- 
section — the same as the two preceding specimens — after which it 
extended quite rapidly and regularly, but in a less ratio, as the 
maximum load, 17,900 pounds, was approached, (see curve of No. 
1166, Plate V,) which was reached with an extension of 17.50 per 
cent.; the resistance then decreased until the specimen broke under 



32 

a load of 17,300 pounds. The Modulus of Rupture of this speci- 
men is 50,800, which is higher than that of any other specimen 
of untreated iron in this series. Rupture took place outside the 
scale; the extension between the initial marks was 20.95 per cent. 
The Modulus of Resilience due to that elongation is 10,032 foot- 
pounds. The area of the cross-section at the fracture was reduced 
to 62.34 per cent, of its original amount; the Modulus of Rupture 
per unit of fractured section is 78,500 pounds. The fracture was 
similar to that of the preceding specimen. 

No. 1 167. Specimen No. 1167 was of the standard length and 
•§ inch in diameter. It was cold-rolled from a bar ff inch in diam- 
eter, and annealed before testing. This specimen passed its Elastic 
Limit under a stress of 33,600 pounds per square inch of cross- 
section, after which it extended rapidly and quite regularly, reach- 
ing its maximum resistance, 15,400 pounds, with an extension of 
13.35 per cent.; it finally broke under a load of 14,900 pounds. 
The Modulus of Rupture was 48,700 pounds. Rupture occurred 
outside the scale. The extension between the initial marks was 
15.80 per cent.; the Modulus of Resilience due to that extension is 
6,777 foot-pounds. The area of section at the fracture was re- 
duced to 64.00 per cent, of its original area, and the Modulus of 
Rupture per unit of fractured section is 76,100 pounds. The frac- 
ture was rough and fibrous ; the surface showed a seam which was 
open in several places. 



CO 



COMPARISON 



OF 



TURNED ip, COLD-POLLED >ND UNTREATED. 

Samples Turned from 2 -Inch Bars. 
D ETERMINAT'ION ' 

OF THE 

Effect of Gold-Rolling upon^ the Innef^ Portion of the Bah, 



LOT No. 2. 



All the specimens in this lot were tested in the same manner as 
those of the preceding. 

No. 1168. Specimen No. 1168 was prepared from a cold-rolled 
bar, 2 inches in diameter, by reducing its diameter in a turning 
lathe to If inches. The distance between shoulders was, in this 
set, 24 inches. This specimen passed its Elastic Limit under a 
stress of 63,900 pounds per square inch, after which it yielded very 
rapidly and broke under a load of 160,900 pounds, which gives it 
a Modulus of Rupture of 66,900 pounds. Rupture took place out- 
side of the scale, the extension between the initial marks being 6 per 
cent. ; the Modulus of Resilience due to that Elongation is 3,877 foot- 
pounds. The area of section at the fracture was reduced to 70.56 
per cent of the original section ; the Modulus of Rupture per 
unit of fractured area is 94,800 pounds. The fracture was quite 
rough and fibrous, with some indications of a granular structure. 

No. 1 169. Specimen No. 1169 was prepared from the same 
2-inch cold-rolled bar, and was turned down to a diameter of 1 j- 
inches. This specimen passed its Elastic Limit under a stress of 
56,600 pounds per square inch of cross- section, after which it ex- 
tended irregularly (see curve of No. 1169, Plate VI), and finally 

3 



34 

broke under a load of 121,000 pounds, having extended 7.65 per 
cent. The Modulus of Rupture is 68,500 pounds, and the Mod- 
ulus of Ultimate Resilience is 4,930 foot-pounds. The area at the 
fractured section was reduced to 71.70 per cent, of the original 
area ; the Modulus of Rupture per unit of fractured section is 
95,500 pounds. The fracture was rough and fibrous, with a partly 
granular structure. 

No. 1 170. Specimen No. 1170 was prepared by turning the 
2-inch bar down to a diameter of 1 inch. This specimen passed 
its Elastic Limit under a stress of 56,700 pounds per square inch 
of section^ after which it yielded quite rapidly and broke under a 
total load of 47,600 pounds, having extended 6.55 per cent. The 
Modulus of Rupture is 60,600 pounds; the Modulus of Ultimate 
Resilience is 3,794 foot-pounds. The area at the fractured section 
was reduced to 68.88 per cent, of the original dimension ; the 
Modulus of Rupture per square inch of fractured area is 86,200 
pounds. The fracture was rough and fibrous, plainly showing in 
some places a granular structure. 

No. 1 171. Specimen No. 1171 was prepared from a bar of 
untreated iron, 2tV inches in diameter, and was turned down to a 
diameter of If inches ; the distance between shoulders was made 
24 inches, as before. This specimen passed its Elastic Limit under 
a stress of 30,900 pounds per square inch of cross -section, after 
which it elongated gradually until it had nearly reached its maxi- 
mum resistance; it then rapidly yielded (see curve of No. 1171, 
Plate VI), and finally broke under a load of 117,100 pounds, 
having extended 30 per cent. The Modulus of Rupture is 48,700 
pounds, and the Modulus of Ultimate Resilience is 14,120 foot- 
pounds. The area at the fractured section was reduced to 58.62 
per cent, of the original section ; the Modulus of Rupture per 
square inch of fractured section is 83,100 pounds. The fracture 
was rough and fibrous. 

No. 1 172. Specimen No. 1172 was prepared from a bar of 
untreated iron, 2tV inches in diameter, by being turned down to a 
diameter of 1J inches. This specimen passed its Elastic Limit 
under a stress of 33,500 pounds per square inch of cross-section, 
after which it extended quite rapidly and pretty regularly until it 
finally broke under a load of 87,420 pounds, having extended 



35 



25.70 per cent. The Modulus of Rupture is 49,500 pounds, and 
the Modulus of Ultimate Resilience is 11,567 foot-pounds. The 
area at the fractured section was reduced to 59.82 per cent, of the 
original ; the Modulus of Rupture per unit of fractured area is 
82,700 pounds. The fracture was rough and fibrous, with signs of 
granular structure. 

No. 1 173. Specimen No. 1173 was prepared from the same 
bar of untreated iron, 2tV inches in diameter, by being turned 
down to a diameter of one inch. This specimen passed its Elastic 
Limit under a stress of 26,000 pounds per square inch of cross- 
section, after which it elongated more and more rapidly, and finally 
broke under a total load of 37,580 pounds, which gives it a Modu- 
lus of Resistance of 47,900 pounds. Rupture occurred outside of the 
scale, the extension between the initial marks being 21.30 per cent., 
and the Modulus of Resilience due to that elongation being 8,^97 
foot-pounds. The area of the fractured section was reduced to 
60.86 per cent, of the original ; the Modulus of Rupture per unit 
of fractured area is 78,700 pounds. The fracture was rough and 
fibrous. 



LOT No. 3. 

Specimens No. 1104 (A, B, C, D, E, F,) and No. 1105 (A, B, 
C, D, E, F,) were tested in the Mechanical Laboratory of the 
Stevens Institute of Technology. The machine used is a Riehli 
Bros. Testing Machine. 




36 

It consists of two strong cast iron columns secured to a massive 
bed-frame of the same material ; above these columns is fastened a 
heavy cross-piece, also of cast iron, containing two sockets, in which 
rest the knife edges of a large scale-beam. The upper chuck is 
suspended by two eye-rods from two knife-edges, J inch to one side 
of centre of a heavy wrought iron block, which is hung by two 
links from two pairs of knife-edges, projecting from the scale-beam 
on opposite sides of the knife-edges of the latter and at equal 
distances from them, the whole making a very powerful differential 
beam-combination. All the knife-edges are of tempered steel, and 
the sockets and eyes are lined with the same material, thus reducing 
friction to a minimum. The load is applied by means of a 
hydraulic press with a fixed plunger and movable cylinder ; to the 
latter the lower chuck is fastened by means of an adjustable staple 
and link. The stress to which the test-piece is subjected is meas- 
ured by means of suspended weights and a sliding poise (the latter 
not seen in the engraving.) The specimen is secured in the chucks 
either by wedge-jaws or cored chucks, according to the specimen 
to be tested. The capacity of the machine is twenty tons. 

The extensions were measured by means of an instrument, in 
which contact is indicated by an " electric contact apparatus." The 
instrument consists essentially of two very accurately made 
micrometer-screws, working snugly in nuts, secured in a frame 
which is fastened to the head of the specimen by a screw-clamp ; it 
is so shaped that the micrometer-screws run parallel to, and equi- 
distant from the neck of the specimen on opposite sides. A 
similar frame is clamped to the lower head of the specimen, and 
from it project two insulated metallic points, each opposite one of 
the micrometer-screws. Electric connection is made between the 
two insulated points and one pole of a voltaic cell, and also between 
the micrometer-screws and the other pole. As soon as one of the 
micrometer-screws is brought in contact with the opposite insulated 
point a current is established, which fact is immediately revealed 
by the stroke of an electric bell placed in the circuit. The pitch of 
the screws is 0.02 of an inch, and their heads are divided into 200 
equal parts ; hence a rotary advance of one division on the screw- 
head produces a linear advance of one ten-thousandth (0.0001) of 
an inch. A vertical scale divided into fiftieths of an inch is 



37 

fastened to the frame of the instrument and set very close to each 
screw-head and parallel to the axis of the screw ; these serve to 
mark the starting point of the former, and also to indicate the num- 
ber of revolutions made. By means of this double instrument, 
the extensions can be measured with great certainty and precision ; 
and irregularities in the structure of the material causing one side 
of the specimen to stretch more rapidly than the other, do not 
diminish the accuracy of the measurements, since half the sum of the 
extensions indicated by the two screws is always the true extension 
caused by the respective loads. 

Every possible precaution was taken during these tests to prevent 
the introduction of errors ; and several special expedients were 
adopted to make the tests as complete as possible, with the object to 
bring out all characteristic properties. 

Before beginning the tests, each specimen was very thinly covered 
with a coating of white lead, on which were marked the following 
lines : 

(1.) Two straight lines on opposite sides of the specimen. 

(2.). Eight lines at right angles to the former and exactly one 
inch apart, dividing the neck of each test-piece into seven equal 
cylinders, each of which was one inch long. 

(3.) Lastly, a helix, of 1.56 inches pitch, was marked on each 
specimen the whole length of its turned part. 

By means of these expedients irregularities of extension can be 
very readily observed and measured. An abrupt change of exten- 
sion would distort the helix, thus indicating the precise spot where 
it occured. The originally equi-distant encircling lines served as 
measure of unequal extensions, and the lines parallel to the axis 
were useful as guides in taking these measurements correctly. 

Fig. 1, Plate 16, represents specimens Nos. 1104 A and 1005^4 
before the test, and Fig. 2 shows No. 1105^4, and Fig 3 No. 1104J. 
after the test. 

In the sketches the specimens are represented half size. 

No. 1 105 A. Specimen No. 1105^4 was cold-rolled. Its length 
between fillets was 7.65 inches; its diameter was 0.875 inch. The 
specimen was secured in the chucks by wedge jaws, and the stress 
applied in increments of a thousand (1,000) pounds; the exten- 



38 

sions were noted for every load, as is seen in the record sheet of 
test of No. 1105^4. It passed its Elastic Limit under a stress of 
54,900 pounds per square inch of cross-section, after which it elon- 
gated more and more rapidly, as can be best seen by studying the 
curve* of 1105.A. It finally ruptured under a load of 39,600 
pounds, or 65,850 pounds per square inch of cross-section, and 
96,000 pounds per square inch of fractured area. The total elon- 
gation was 0.775 inch, or 11.07 per cent., which was distributed 
along the bar as follows : 

Cylinder a extended 0.065 inch. 



u 


b 


'< .07 " 


a 


c * 


.08 " 


a 


d 


' .07 " 


a 


e { 


< .095 " 


a 


f l 


' .30 t( 


a 


9 


'< .095 " 


lsioi 


i, 


- 0.775 inch. 



Total extension, 

The portion abed had reduced to 0.84 inch, (a slightly more, 
c slightly less,) in diameter ; e and g tapered toward/, in the mid- 
dle of which part it broke. The diameter of the fractured area 
was reduced to 0.725 inch. The fracture was rough, but not 
ragged ; it had a silky texture, and showed traces of granular 
structure. The surface of the specimen became slightly undula- 
ted, but did not exhibit the fibre, and showed no seams. This 
specimen had a Modulus of Elasticity of 26,871,000 ; its Modulus 
of Ultimate Resilience was 7,200 foot-pounds, and that of its Elas- 
tic Resilience 109.76 foot-pounds. 

*jS"ote. — The great extension for the load, 29,000 pounds, shown in the table, 
and more plainly seen on the curve, is due to the breaking of one of the wedges 
in the chuck. To provide against further accidents of this kind the specimens 
Nos. 1105 (A, B, C, D,) and Nos. 1104 (A, B, C, D.) had threads cut on both 
ends and a round nut screwed on, as shown in Fig. 1, Plate 16; this adapted 
the specimen to the shoulder »jaws. Specimens E and F of each number were 
left plain, since the torsional stress necessarily brought on such slender pieces 
in cutting the threads might have strained them beyond the Elastic Limit, 
which would alter their resistance for tension, and thus render them of little 
or no value. 



39 

No. 1 104 A. Specimen No. 1104J. was of untreated iron, mid 
was of the same dimensions as the preceding. The stress was ap- 
plied by increments of thousand pounds, and the extensions noted 
for each load were as shown in the appended record sheet. It 
passed its Elastic Limit under a stress of 14,000 pounds, or 23,300 
pounds per square inch of cross-section, after which the elongations 
increased rapidly and quite uniformly, as is shown by the smooth- 
ness of the curve ; with 30,000 pounds of load, equivalent to 49- 
890 pounds per square inch of cross-section, the test was discon- 
tinued.* The specimen had elongated 1.43 inches, or 20.43 per 
cent.; this elongation was exceedingly uniform, and the diameter 
quite uniformly reduced to 0.82 inch. Forty- eight hours after- 
ward the specimen was again put in the machine and the test con- 
tinued ; the stress was applied as before, up to 20,000 pounds, and 
then increased by increments of 2,000 pounds. Under a total load 
of ^4,000 pounds, or 56,542 pounds per square inch of cross-sec- 
tion, it ruptured just below the nut in the upper chuck ; it was also 
cracked near the nut in the lower chuck. New threads were cut 
and the specimen finally ruptured at e, (Fig. 3,) under a total load 
of 35,150 pounds, equivalent to 58,450 pounds per square inch of 
original cross-section, and 122,452 pounds per square inch of frac- 
tured area. The total extension was 1.84 inches in 7 inches, or 
26.30 per cent. This extension was distributed as follows : 

Cylinder a extended 0.235 inch. 



u 


b 


a 


.26 " 


u 


c 


a 


.245 " 


ll 


d 


a 


.22 " 


u 


e 


a 


.40 " 


a 


f 


u 


.24 " 


u 


9 


it 


.24 " 


Total extension, 


1.84 inch. 



The diameters of the portions abed and/ g do not vary much 
from 0.782 inch. The diameter of the fractured area was 0.708 
inch. The fracture differs from that of the preceding test piece 

*Note. — The specimen had extended beyond the range of the machine, so 
that a few changes had to be made before the testing could go on. 



40 

only in exhibiting a much more granular structure showing numer- 
ous clusters of irregular facets, especially near the edges of the 
fracture. The fracture at the end of the specimen exhibits the 
granular structure still more fully, nearly one-half of it being 
entirely of this character. This structure is often said to be indic- 
ative of a deficiency in ductility ; but the facts in the present case 
certainly show that this is, at least, not invariably the fact. It may 
here have been due to the intermitted test. 

Judging from the appearance of the curve, and still more con- 
clusively from the fact that it gave way in the chucks, at a part 
which had been but slightly affected by the stress brought upon it 
during the first trial, under a load of 53,444 pounds per square 
inch of the original cross-section of that part, it is evident that 
this specimen would very probably not have resisted much more 
than 50,000 pounds per square of such cross-section could it have 
been broken at the first pull. After resting two days its molecules 
seem to have had time to rearrange themselves, and thus to have 
made the specimen stronger than before. This is indicated in the 
sudden rise seen in the curve No. 1104A at a. (See Piate VII.) 

Considering it as a new specimen having a diameter of 0.82 inch, 
it surpasses even the best cold-rolled specimen in this collection in 
ultimate strength, and it has considerably higher Elastic Limit ' 
but it falls below the average in ductility. Consulting the record 
of No. 1104^1, or glancing at the curve No. 1104^/, Plate VII, it 
is seen that it does not pass its Elastic Limit until after it has been 
strained above 60,000 pounds per square inch of cross-section, and 
that it bears over 66,800 pounds per square inch of cross-section 
before rupture takes place. 

The Modulus of Elasticity of this specimen was only 23,860,000; 
its Modulus of Elastic Resilience was 14.91 foot-pounds, and its 
Modulus of Ultimate Resilience 12167.5 foot-pounds. The latter 
is of course unduly augmented by the rest given the specimen after 
having been strained almost to its point of rupture. 

I infer from the results of the peculiar treatment of this test 
piece, that the cold-rolling of this metal had not been carried far 
enough to produce the maximum effect attainable by the application 
of this process. 

No. T105B. Specimen No. 11055 was cold-rolled; it had a 



41 

diameter of 0.75 inch, and a length between fillets of 7.5 inches. 
The load was applied and the extensions noted as before. (See 
record sheet of 11055.) Under a stress of 56,600 pounds per 
square inch of cross-section, it passed its Elastic Limit, the exten- 
sions increasing rapidly but regularly. It finally broke under a 
total load of 29,000, or 65,640 pounds per square inch of cross- 
section, and of 93,000 pounds per square inch of fractured area. 

The total elongation was 0.63 inch in 7 inches^ and was dis- 
tributed as follows : 

Cylinder a extended 0.06 inch. 



a 


b 


a 


.06 " 


a 


c 


k 


.06 " 


(( 


d 


c< 


.07 " 


u 


e 


a 


.07 " 


a 


f 


i( 


.09 " 


i( 


9 


a 


.22 " 


Total extension, 


0.63 inch 



The diameters of the several parts abode were very nearly 
uniformly reduced to 0.72 inch. The diameter of the fractured 
section was rough and had a silky texture, and a small portion of 
it showed a granular structure. The surface was but very slightly 
undulated, and showed no fibre. The Modulus of Elasticity was 
27,829,000. The Modulus of Elastic Eesilience was 69.59 foot- 
pounds, and that of Ultimate Resilience was 5892.5 foot-pounds. 

No. 1104B. Specimen No. 11045 was of untreated iron. Its 
dimensions were the same as those of the preceding. The stresses 
w r ere applied and observed as before. (See appended record sheet 
of No. 11045.) 

This specimen passed its Elastic Limit under a stress of 23,800 
pounds per square inch of cross-section, after which the elongations 
increased more and more rapidly but quite regularly (see curve). 
Under a load of 38,500 pounds per square inch it fairly began to 
"flow," stretching over 5 per cent, with an increment of 1,000 pounds 
of load ; it then again recovered its resisting power, as is indicated by 
the counterflexure of the curve. The next increment of 1,000 pounds 



42 

of load produced an elongation of 1.5 per cent. only. The piece 
then extended more rapidly but regularly, and finally ruptured 
under a total stress of 21,800 pounds, or 49,330 pounds per square 
inch of original cross-section, and of 79,400 pounds per square 
inch of fractured area. 

The total elongation was 1.51 inches in seven inches, or 21.67 
per cent.; it was distributed as follows : 

Cylinder a extended 0.12 inch. 



it 


b 


.14 « 


a 


c " 


.13 " 


a 


d 


.40 " 


a 


e u 


.305 " 


a 


/ " 


.24 " 


a 


9 " 
[tension, - 


.175 " 


Total e? 


1.51 inch. 



The portion a b c had reduced to a diameter of 0.69 inch ; the 
fracture occurred, in d, near e, as shown in fig. The diameter of the 
fracture was 0.592 inch ; it was rough, had a silky, fibrous texture, 
and showed no traces of granulation in structure. The surface of 
the cylindrical portion was undulated and exhibited a fibrous 
structure, especially near the fracture, where a few small seams also 
appeared. 
. The Modulus of Elasticity was 25,679,000. The Modulus of 
Elastic Resilience was 18.77 foot-pounds, and the Modulus of 
Ultimate Resilience was 8607.5 foot-pounds. 

No. 1105C. Specimen No. 1105(7 was cold-rolled. Its diame- 
ter was 0.25 inch, and its length between fillets 7.45 inches. The 
stress was applied by increments of 800 pounds (see appended 
record of test). This specimen is remarkable for the wonderful 
regularity of its extensions with equal increments of stress ; the 
greatest variation in extension with the same increment of stress 
until 6,200 pounds total load is reached, was only 0.00,005 inch, 
(see record of No. 1105(7.) 

The Elastic Limit was fully passed under a tojtal stress of 17,- 
000 pounds, or 55,4C0 pounds per square inch of cross-section. 



43 

After passing the Elastic Limit it elongated more and more rapidly, 
but very regularly, until it finally broke under a total stress of 
20,450 pounds, or of 66,650 pounds per square inch of original 
cross-section, and 90,6u0 pounds per square inch of fractured 
area. 

The total elongation was 0.645 inch in 7 inches, or 9.22 per 
cent., which was distributed as follows : 

Cylinder a extended 0.06 inch. 



a 


b 


a 


.065 " 


it 


C 


a 


.06 }< 


a 


d 


it 


.06 " 


a 


e 


u 


.14 « 


ti 


f 


a 


.18 " 


u 


9 


it 


.08 " 



Total extension, - - 0.645 inch. 

The portion abed was reduced very regularly, and measured 
0.605 inch in diameter; the diameter of the fractured area was 
0,536 inch. The fracture was very similar to the preceding ; it 
had a fibrous, silky texture, and showed no trace of granular 
structure. The cylindrical surface became very slightly undulated 
under test, but revealed no seams ; a trace of a seam appeared in /, 
near the fracture. 

This specimen had a Modulus of Elasticity of 25,743,000 ; its 
Modulus of Elastic Resilience is 71.47 foot-pounds, and that of 
Ultimate Resilience is 56.40 foot-pounds. 

No. 1104C. Specimen No. 1104(7 was of the same untreated 
iron : the dimensions were the same as those of the preceding 
specimen, and it was tested in the same manner, (see appended 
record of test.) It passed its Elastic Limit under a total stress of 
7,400 pounds, or 24,000 pounds per square inch of cross-section. 
After passing the Elastic Limit, the "flow" of the molecules was 
twice retarded (see curve of No. 1104C, Plate VII,) the first time 
under a total load of 9,000 pounds, and the second time under 
12,000. The extension then became regular and more and more 



44 

rapid until rupture occurred under a total load of 15,500 pounds, 
or of 50,520 pounds per square inch of cross-section, and of 90- 
100 pounds per square inch of fractured area. 

The total elongation was 1.72 inches in 7 inches, or 24.571 per 
cent., and was distributed as follows : 



Cylinder a extended 0.185 inch. 



« b 


: .2 • " 


a G 


.2 " 


d 


09 a 


e 


' 0.315 " 


" f < 


.34 " 


" 9 ' 


■ .26 " 


Total extension, 


1.72 inches 



The portion abed, was reduced to 0.542 inch in diameter, d 
decreasing toward e. Rupture took place between e and /. The 
diameter of the fractured area was 0.48 inch ; the fracture was 
rough, of a fibrous, silky texture, and showed decided indications 
of granular structure. The surface became quite undulated and 
exhibited a fibrous structure. The Modulus of Elasticity was 
somewhat high — 30,363,000 ; the Modulus of Elastic Resilience 
was 18.09 foot-pounds and the Modulus of Ultimate Resilience 
was 10,875 foot-pounds. 

No. 1105D. Specimen No. 1105D was cold-rolled; it had a 
diameter of 0.5 inch and a length between fillets of 7.4 inches. 
The stress was applied in increments of 300 pounds and the ex- 
tension noted for every addition of load, as before (see record of 
test). Although there is a disproportionate increment of extension 
with the increment of load passing from 5,000 to 5,300 pounds, 
as is noticeable, both in the curve and the record, it did not pass 
its Elastic Limit fully, until the total load, 11,000 pounds, or 
56,800 pounds per square inch of cross-section, had been reached. 
The extensions then increased more and more rapidly ; but no 
noticeable " flow " set in until the load had reached 61,000 pounds 
per square inch of cross-section. The specimen finally broke 



45 

under a total stress of 13,000 pounds, or 66,200 pounds per square 
inch of cross-section, and 91,600 pounds per square inch of frac- 
tured area. 

The total elongation in 7 inches was 0.57 inch, or 8.14 per cent., 
which was distributed as follows : 

Cylinder a extended 0.055 inch. 



" b 


.06 " 


" G 


.06 " 


" d 


.065 " 


e 


.07 .« 


" / " 


.19 " 


" 9 " 


.07 " 


Total extension, 


0.57 inch. 



The diameter of the fractured area was 0.425 inch, and that of 
the portion abed, was 0.484 inch ; e and g tapered slightly 
toward/, where rupture occurred. The fracture is rough, fibrous, 
and of a silky texture, and shows no traces of a granulation. The 
cylindrical surface was but very slightly undulated and shows no 
traces of fibre or seams. The Modulus of Elasticity was 28,989,000; 
the Modulus of Elastic Resilience was 71.47 foot-pounds and the 
Modulus of Ultimate Resilience was 5072.5 foot-pounds. 

No. 1104D. Specimen No. 1104Z) was of untreated iron, and 
had the same dimensions as the preceding. The stress was applied 
with the same increments and elongations which were noted as be- 
fore. (See records.) It passed its Elastic Limit under a stress of 
4,700 pounds, or 23,900 pounds per square inch of cross-section, 
after which the elongation increased in the usual manner with 
three successive increments of stress ; but the next increment pro- 
duced a disproportionately large extension, and the next a dispro- 
portionately small extension, as is shown by the counterflexure of 
the curve of No. 1104D, Plate VIII. The specimen then elon- 
gated rapidly but regularly at a slightly diminishing rate toward 
the close of the test, as is indicated by the slight upward concavity 
in that part of the strain-diagram. The specimen finally broke 
under a total stress of 10,000 pounds, or of 50,980 pounds per 



46 

square inch of cross-section, and 93,600 pounds per square inch of 
fractured area. 

The total elongation was 1.3 inches in 7 inches, which was dis- 
tributed as follows : 

Cylinder a extended 0.14 inch. 



a 


b 


(< 


.15 " 


u 


C 


a 


.145 " 


a 


d 


u 


.145 " 


(. 


e 


a 


.145 <- 


(C 


f 


a 


.34 " 


ti 


9 


n 


.235 " 



Total extension, - - 1.3 inch. 

The diameter of the portion abed e, was reduced to 0.469 inch ; 
and that of the fractured section measured 0.369 inch. The frac- 
ture was rough, of a silky, fibrous texture ; the surface was moder- 
ately undulated, but did not exhibit the fibrous structure, except 
in the portion drawn down, where also a small seam appeared. 

The Modulus of Elasticity was 30,150,000; the Modulus of 
Elastic Resilience, 26.33 foot-pounds, and that of Ultimate Resil- 
ience 7757.5 foot-pounds. 

No. 1105E. Specimen No. 1105i?, of cold-rolled iron, was 0.375 
inch in diameter and 7.375 inches in length between fillets. The 
stress was applied in increments of 300 pounds, and the elongations 
were noted for every load. (See appended record.) This specimen 
shows some irregularities of resistance within the Elastic Limit, as 
is shown both by the records and by the curve. Between the loads 
28,928 and 33,500 pounds per square inch of cross-section, the ex- 
tensions for equal increments of load are disproportionately large. 
The Elastic Limit was passed under a total load of 6,000 pounds, 
or of 54,300 pounds per square inch of cross-section, after which 
the piece stretched very rapidly, and finally broke under a total 
load of 7,000 pounds, or of 63,400 pounds per square inch of 
cross-section, and 99,000 pounds per square inch of fractured area. 

The total elongation was 0.51 inch in 7 inches, or 7.286 per 
cent., which was distributed as follows : 



47 
Cylinder a extended 0.05 inco. 



b 


u 


.05 


<i 


c 


a 


.06 


a 


d 


u 


.05 


a 


e 


is 


.18 


a 


" f 


a 


.05 


a 


u g 


a 


.07 


u 


Total extension, 


- .51 inches. 



The diameter of the portion abed was reduced 0.36 inch, and 
the fractured section measured 0.3 inch. The fracture was rou^h, 
and of a fibrous and silky texture : it showed traces of granulation. 
The cylindrical surface had become slightly undulating and showed 
a few slight seams in the portion d e/near the fracture. 

The Modulus of Elasticity was but 22,261,000. The Modulus 
of Elastic Resilience was 163.13 foot-pounds, and that of Ultimate 
Resilience 4,247.5 foot-pounds. The irregularities of resistance 
of this specimen within the Elastic Limit very probably indicate 
defects in its internal structure, minute flaws. The low co-efficient 
of Elasticity, the low Modulus of Rupture, and also the low Mod- 
ulus of Ultimate Resilience corroborate this supposition. 

The Modulus of Elastic Resilience is exceptionally high, but it 
cannot be considered entirely reliable on account of the dispropor- 
tionate elongations within the Elastic Limit. 

No. 1104E. Specimen No. Il04i£ was of untreated iron of the 
same dimensions as the preceding, the stress being applied in the 
same manner and the elongations noted as before. (See appended 
record of tests.) This test-piece had fully passed its Elastic Limit 
with a total load of 2,300 pounds, or 20,800 pounds per square 
inch of cross-section. After passing the Elastic Limit it elongated 
with regularly increasing rapidity until the load became 33,500 
pounds per square inch, when the extension was suddenly arrested. 
(See curve of No. 11Q4JEJ, Plate VIII.) And with the next in- 
crement of 500 pounds — 4,529 pounds per square inch of cross- 
section — the increment was not much greater than within the 
Elastic Limit for the same increment of load. An additional load 
of 50 pounds — 440 pounds per square inch of cross-section — pro- 



48 

duced an elongation of 2.448 per cent., after which the "flow " was 
again suddenly arrested, the piece extending only 0.081 per cent., 
with an increment of 350 pounds — 4,088 pounds per square inch 
of cross- cection. The next increment of 300 pounds produced an 
elongation of 6.189 per cent., after which "flow" was arrested a 
third time, and an increment of 200 pounds of stress was required 
to overcome this new molecular resistance. It then yielded rap- 
idly, though considerably less in proportion to the load than any 
other specimen of this lot, as will be seen on examination of the 
inclination of the curve. It broke under a total stress of 5,800 
pounds, or 52,540 pounds per square inch of cross-section, and 
97,700 pounds per square inch of fractured area. 

The sudden offsets in the curve show the peculiar behavior of 
this specimen very plainly. 

The total elongation was 1.44 inches in 7 inches, or 20.57 per 
cent. ; it was distributed as follows : 

Cylinder a extended 0.155 inch. 



t; 


b 


a 


.195 


u 


« 


G 


u 


.195 


tc 


a 


d 


a 


.195 


iC 


a 


e 


a 


.35 


u 


u 


/ 


a 


.195 


u 


a 


9 
[on, 


a 


.155 


a 


Total extensi 


- 1.44 i 


no 



The diameter of the portion abed was reduced to 0.343 inch 
and that of the fractured area measured only 0.275 inches. The 
fracture was rough, and generally of a silky texture ; but it had 
decided traces of granular structure. The surface was undulated 
and indicative of a fibrous structure : a small seam appeared near 
the fracture. 

The Modulus of Elasticity of this specimen was 27,038,000 ; 
the Modulus of Elastic Resilience was 26.25 foot-pounds, and that 
of Ultimate Resilience was 8,500 foot-pounds. 

No. 1105F. Specimen No. 1105.F was " cold- rolled ; ' its 
diameter was 0.25 inch, and its length between fillets 7.25 inches. 



49 

The stress was applied in increments of 400 pounds, and the 
extensions were noted for every load, as before (see record of No. 
1105.F). This specimen did not elongate regularly within the 
Elastic Limit ; the variations, however, were too small to be notice- 
able in the curve ; the Elastic Limit was passed under a load of 
50,000 pounds per square inch of cross -section, after which it 
suddenly yielded (see curve of 1105i^, Plate VIII) extending 1.96 
per cent, with an increment of 200 pounds of load, or 5,074 pounds 
per square inch of cross-section. It then suddenly stiffened, 
elongating but 0.137 per cent, with the next increment of 200 
pounds, and finally broke under a load of 3,175 pounds, equivalent 
to 64,660 pounds per square inch of cross-section, and 91,800 
pounds per square inch of fractured area, having extended only 
0.24 inch in 7 inches, or 3.43 per cent. 

This elongation was distributed as follows : 

Cylinder a extended 0.02 inch. 



a 


b 


a 


.02 " 


tc 


c 


a 


.02 " 


a 


d 


a 


.02 " 


it 


e 


ti 


.02 " 


u 


J 


a 


.025 " 


tt 


9 
ion ; 


a 


.115 " 


Total extens 


.24 int 



The portion a b c d e f was reduced to 0.24 inch diameter, and 
the fractured area measured 0.21 inch in diameter. The surface re- 
mained almost entirely unaltered. The fracture was rough, had 
generally a silky, fibrous texture, and showed some traces of granu- 
lar structure. 

The Modulus of Elasticity was very high — 35,553,000 pounds; 
the Modulus of Elastic Resilience was 51.163 foot-pounds, and 
that of Ultimate Resilience was 1,945 foot-pounds. 

No. 1104F. Specimen No. 1104.F was of untreated iron, and 
was of the same dimensions as the preceding. The loads were 
applied in increments of 400 pounds, and the elongations were 
noted for each load (see record of No. 1104jF). This specimen, like 

4 



50 

the preceding, elongated irregularly within the Elastic Limit, 
which it passed at a total stress of 1,100 pounds — 22,400 pounds 
per square inch of cross-section. After the Elastic Limit was 
passed, the piece elongated rapidly and quite regularly, until the 
load had been increased to 37,684 pounds per square inch of cross- 
section, at which point (see curve of No. 1104.F) it began to yield 
rapidly, and broke under the comparatively low stress of 2,110 
pounds, or 42,980 pounds per square inch of cross-section. 

The total elongation was 1.185 inches in 7 inches, or 16.928 
per cent., which was distributed as follows : 

Cylinder a extended 0.04 inch. 



u 


b 


« 


.155 " 


i( 


G 


a 


.155 " 


<( 


d 


a 


.155 " 


a 


e 


u 


.18 " 


a 


f 


u 


.235 " 


a 


9 
iion, 


a 


.265 " 


Total exteng 


1.185 inches. 



The diameter of the portion bed was 9.228 inch, and that of 
the fractured area, 0.185 inch. The fracture was rough, of a 
fibrous and silky texture, and showed but very slight indications of 
granulation. The cylindrical surface also showed the fibrous struc- 
ture. 

The Modulus of Elasticity was almost as high as in the preced- 
ing specimen, 33,317,000 pounds ; the Modulus of Elastic Resil- 
ience was 23.52 foot-pounds, and that of Ultimate Resilience was 
6,535 foot-pounds. 






CONCLUSIONS. 



I. THE UNTKEATED IRON. 

In reviewing the results which were discussed in the preceding 
pages, we find : 

1st. That the untreated iron which was tested full size has an 
average breaking strength of 48,700 pounds per square inch of 
cross-section, and that the ultimate strength per unit of area of sec- 
tion decreases gradually as the diameter increases. Neglecting the 
size D, (1^ inches in diameter) which is exceptionally low, we get 
a tolerably smooth curve (BB, Lot II, Plate IX), which starting 
with the smaller size E r (ff inch diameter), having a Modulus of 
Rupture equal to 50,500 pounds per square inch of cross-section, 
the curve sinks very gradually, at first, toward the larger sizes, but 
more rapidly as it approaches the largest size A, (2 T ^ inches diam- 
eter), of which the strength is only 46,700 pounds per square inch 
of cross-section, or 3,000 pounds below the average. 

2d. That the Elastic Limit* is passed under an average stress of 
27,600 pounds per square inch of cross-section, or 56 per cent, of 
its ultimate strength. The curve of average Elastic Limits 
deviates much more from a straight line than that of Ultimate 
Strengths, and does not run parallel with it, thus indicating that 
the Elastic Limit and the Ultimate Strength are not directly 
related. 

* The Elastic Limits as obtained from the tests made at the works of the 
Keystone Bridge Co., are considerably higher than those obtained from the 
specimens tested in the Mechanical Laboratory of the Stevens Institute of 
Technology. This will be seen on examining the tables, giving the summary 
of results, or comparing the curves C / C / and E / E / , with G / G / and D / D / J and 
' A / A / with E'F'. Plate IX. 

This difference, since it occurs to almost the same extent in the turned speci- 
men as in those tested full size, is very probably not so much (or perhaps not at 
all) due to the superiority of the surface-metal as to the method of testing and 
the manner in which the extensions were marked, the mark denoting the ex- 
tension for the corresponding load being made before the latter had time to 
produce the full effect on the specimens. 



52 

oil. That the total extension* averages about 25 per cent., and 
that the fractured section is reduced on an average to 63.5 per cent, 
of its original area. 

4th. That the results obtained with the specimens, which were 
turned from a bar 2 inches in diameter to sizes varying from J- to 
If inches, compare favorably with those tested full size as they 
came from the rolls, the turned specimen having an average break- 
ing strength of 49,500 pounds per square inch of cross-section, 
which is 800 pounds greater than that of the unprepared specimens, 
and 1,000 pounds greater than the average strength of the bar from 
which these specimens were prepared. 

5th. That excepting the size F, (J inch diameter) which, having 
a strength of 42,900 pounds per square inch only, is low and 
very probably test piece was unsound — the strength increases as the 
diameter decreases in a greater ratio than in the cases of the un- 
turned specimens. (See curves, Plate IX.) This indicates that 
the interior portion of the bar is stronger f than the exterior. 

6th. That the average Elastic Limit of Lot III is 23,000 pounds 
per square inch, or 45.7 per cent, of the ultimate strength, while 
that of Lot II is 30,000 pounds J per square inch, or 61 per cent, 
of the ultimate strength, the latter being also higher than the 
average Elastic Limit of Lot I. 

7th. That the average total extension of the turned specimens is 
quite as high as that of those unturned, and that it decreases with 
the diameter. Although there appears to be a tendency in the 
same direction in the unturned bars, it cannot be positively 

*The true average per cent, of extension could not be determined, since only 
a few of the specimens broke between the initial marks. But the figure given 
above is not far wrong, and is on the safe side ; the partial extensions, as measured 
between the initial marks, average about 20 per cent. The Modulus of Kesil- 
ience being a direct function of the extension, is also slightly too small. 

-j- The indicated increase of strength toward the centre of the bar is contrary 
to the general opinion of engineers, according to which the outer shell is the 
stronger metal. The above evidence being based on tests of but one specimen 
of each size, we are not justified in putting it forward as positively proven be- 
fore it has been corroborated by further experiment. 

J The difference between the Elastic Limits of Lots II and III is undoubt- 
edly partly due to the method of testing; whereas, that between those of Lots 
I and II, can only be attributed to the material itself. 



53 

asserted, because but a few breaks occurred which give evidence on 
this point. 

8th. That the reduction of section at the point of rupture was 
greater in the turned than in the unturned specimens, the average 
reduced area of the former being but 59.1 per cent, of the original, 
which is 4.4 per cent, less than that of the unturned specimen. 

Consulting Table G, we find that although the total extension 
decreases with the diameter, the reduction of section increases, and 
in a much greater ratio. 

9th. That the average Modulus of Elastic Resilience* is 21 31 
foot-pounds, and that of Ultimate Resilience is 9,074 foot-pounds, 
the former being only 0.23 per cent, of the latter. Therefore, 
although the work necessary to be exerted in breaking a specimen 
of untreated iron may be very considerable, it requires only a very 
small fraction of that work to strain it beyond its Elastic Limit, 
*. e:, to produce a permanent elongation which may be sometimes 
as serious a result as actual fracture. 

II. COLD-ROLLED IRON. 

Summing up the results of tests obtained with cold-rolled iron, 
which were individually noticed in the preceding pages, we ob- 
serve : 

1st. That the specimens, which were tested of full size and just 
as they were taken from the rolls, have an average breaking 
strength of 68,600 pounds per square inch, and that this ultimate 
strength increases as the size decreases. (See curve of breaking 
loads AA, Lot I, Plate IX.) Beginning with the largest size, A, 
(2i% ♦inches diameter,) of which the breaking load is 66,200 pounds 
per square inch, the ultimate strength increases regularly to size 
D, (1 inch diameter,) which has a Modulus of Rupture of 68,200 
pounds. This is below the average breaking strength, which 
figure is carried above its proper amount by the exceptionally high 
resistance of E' (-| inch diameter,) which has an average Modulus 
of Rupture of 73,800 pounds. 

*For Lots I and II, on account of the method of testing, the Modulus of 
Elastic Resilience could not be satisfactorily determined, and the Modulus of 
Ultimate Resilience being in most cases only partial, is not comparable with 
that of Lot III. 



54 

2d. That the average Elastic Limit is 59,600 pounds per square 
inch, nearly 87 per cent, of the ultimate strength. 

Although the curve of Elastic Limits, A' A', is more regular 
than that of the untreated iron, C C, it confirms the deduction 
already made that the Elastic Limit is not necessarily proportional 
to the ultimate strength of the material. The curves of Elastic 
Limits, E' E', G' G ; , F' F', D / D', and especially B' B', similarly 
indicate this independence; the latter curve is that of annealed 
cold-rolled iron, of which the breaking weight does not exceed 
that of the untreated iron ; it shows a much higher Elastic Limit 
than the latter. 

3d. That the total extension is small in comparison with that 
of untreated iron ; it averages but 6 per cent. The extension of the 
largest size, A, (2^6 inches diameter,) which was quite granular in 
structure, was but 2.75 per cent., and that of the smallest size, E, 
(f inch diameter,) was 4.5 per cent. Size C (1t 5 f inches diameter,) 
was the most ductile, elongating 8.3 per cent. In these cases the 
ductility does not decrease with diameter, as is the case with un- 
treated iron. 

4th. We find in comparing the results here obtained with 
■ those given by the specimens of Lots II and III, which were 
turned from the same cold rolled bar, 2 inches in diameter, that 
the Modulus of Rupture is 65,300 pounds, which is 1,600 pounds 
less than that 'of the bar from which these specimens were prepared, 
and further, by studying the curve of breaking loads D D,E E y * it 
is seen that the Ultimate Strength gradually diminishes with the 
diameter, which shows that although the metal was not equally 
affected throughout the whole bar, the effect was very marked, even 
on the smallest size, of which the breaking load per square inch 
was only 2,200 pounds less than that of the full-sized bar, and was 
16.200 pounds greater than the Ultimate Strength of the untreated 
bar of the same iron. 

5th. That the average Limit of Elasticity of Lots II and III is 

■*The irregularities of the dotted curves of Lots II and III must not be 
attributed to the greater irregularities in the material which was turned to size 
than in that which was tested full size, but to the fact that each observation was 
obtained from a single test, aod not from several, as in Lot I. If three or 
more sppcimens of the same size and material could have been tested, the curve 
would undoubtedly have been much smoother. 



65 

reached under a load of 57,000 pounds per square inch — that of 
Lot II at 59,000 pounds, and that of Lot III at 54,800 pounds 
per square inch. This difference, as already stated, is very proba- 
bly partly due to the method of testing. The Elastic Limit of 
Lot III is 83.5 per cent, of its Ultimate Strength ; therefore, a 
structure of cold-rolled iron may be strained above 0.83 of its 
Ultimate Strength before it becomes injured by permanent distor- 
tion, whereas untreated iron reaches this stage with but 0.45 of its 
breaking load. 

6th. That the average ductility of the turned specimens (Lots 

II and III) is about the same as that of the unturned (Lot I), or 6 
per cent., but is less than that of the full-sized bar from which 
these specimens were prepared. The average elongations of Lot 

III separately, approaches that of the full-sized bar, but falls below,* 
the measurable extension of the latter being 8.3 per cent. The 
extension of Lot I appears to be independent of the diameter of 
the specimen, while in Lot III the elongation decreases with the 
diameter. 

7th. That the reduction of area in the cold-rolled iron is much 
more nearly proportional to the extension than in the untreated 
iron, indicating that the process of cold-rolling renders the bar 
much more homogeneous. 

8th. That the average Modulus of Resilience is 90.26 foot- 
pounds, which is 1.8 per cent, of the average Modulus of Ultimate 
Resilience, the latter being 5,000 foot-pounds. With untreated iron 
it was 0.23 per cent. The Modulus of Ultimate Resilience of the 
cold-rolled iron is 56 per cent, of that of the common iron ; but 
comparing the Modulus of Average Elastic Resiliences with each 
other, we see that they are to each other as 1:4.2 nearly, i. e., it will 
require more than four times as much work to be expended to dis- 
tort a structure of cold-rolled iron as will be required to strain one 
of similar proportions, but built of common iron. 

9th. Comparing the fractures, we infer that cold-rolling does not 
produce crystalization ; many of the specimens, both cold-rolled 
and untreated, showed a granular structure plainly, and without 
exhibiting deficiency in ductility as a consequence. 

*The total extension of the full-sized bar could not be ascertained, since all 
specimens broke outside of the marks 



56 



III. ANNEALED COLD-ROLLED IRON. 

The results obtained with annealed cold-rolled iron show : 

1st. That the Average Ultimate Strength is reduced by anneal- 
ing in these cases to its original figure very nearly, and that its 
value increases as the diameter decreases, from 46,300 pounds per 
square inch, the Modulus of Rupture of size A r (2t 7 6 inches diam- 
eter) to 50,900, the breaking load of size D' (1 inch diameter). 
Size E r (f inch diameter) had a breaking load of only 48,700 
pounds per square inch ; it very probably was flawy. 

2d. That the Average Elastic Limit is 32,000 pounds per square 
inch, considerably higher than that of the untreated iron, which 
rendered this limit at 27,600 pounds. 

3d. That the average total extension, 15 per cent.,* is interme- 
diate between that of the cold-rolled and that of the untreated 
iron ; it seems to be independent of the diameter of the specimens. 

4th. That the fractured section was reduced to 62.5 per cent, of 
its original diameter. This reduction seems to be not only inde- 
pendent of the original diameter, but also independent of the total 
extension. Size C f extended only 9.5 per cent., while it shows "a 
contraction of the fractured section to 57 per cent., whereas size D r 
extended over 16 per cent., and had a fractured section of which 
the area was 67,25 per cent, of the original. 

5th. The Modulus of Ultimate Resilience, depending as it does 
upon the Elastic Limit, Ultimate Extension, and Modulus of Re- 
sistance, must be intermediate between that of cold-rolled and that 
of untreated iron, being greater than the former, and less than the 
latter. Thus by annealing, the cold-rolled metal loses greatly in 
all its peculiarly valuable qualities, but retaining, nevertheless, a 
higher tenacity and higher Elastic Limit, with reduced ductility 
as compared with ordinary iron. 

*The average total extension could not be exactly obtained, as many of the 
specimens broke outside of the marks. 






57 



REPORT 



o x 



TESTS BY TRANSVERSE STRESS 



V 

OF 



UNTREATED AND COED-ROLLED 

WROUGHT IRON SHAFTING. 



The object of the following investigation is the determination of 
the effect upon its transverse strength of cold-rolling wrought iron 
shafting of different diameters, comparing the cold-rolled metal 
with the same material hot-rolled. 

The samples tested were made companion pieces to those con- 
stituting Lot I, tested by tensile stress, and reported upon in the 
preceding pages. 

There were thirty-five samples in all, viz : 

First, 15 of common or hot-rolled iron, comprising five sizes, 
nominally:* A=2 T 9 5 inches in diameter; B=2 T ^ ; C^=lf ; 
D=1 T V; E=|f. Secondly, 15 samples of cold-rolled iron, also 
of five sizes; A'=2 T 7 g- inches in diameter; B r =2 ; C'^ly^-; 
D'=l ; E r =f . Thirdly, 5 samples of cold-rolled and annealed 
iron, one of each of the cold-rolled sizes. 

The lengths of the test-pieces were 40 inches or more. In this 
report the sizes will always be designated by the letters A to E, 
as above. 

*The diameters of the untreated iron, as obtained by actual measurement, 
and as given upon the record sheets, and upon which the calculations are based, 
do not exactly agree with the above. The nominal diameters of the cold-rolled 
bars, however, accord with the measurements made upon them. 



58 



DESCRIPTION OF THE TRANSVERSE TESTING 

MACHINE. 

The machine employed in testing by transverse stress is readily 
understood from the accompanying cut. 




It consists of a Fairbanks Scale, on the platform of which rests 
a heavy cast iron beam, C, to which are fastened the supports, D, 
D, at the required distances apart. The pressure is applied by 
means of the hand wheel on the upper end of the screw, K, which 
screw passes through the nut, E, and terminates in the sliding 
cross-head, I. This cross-head serves both as a guide and as a 
pressure block. The test-piece, L, rests upon mandrels mounted 
upon the supports, D, D, at the required distance apart. The loads 
are weighed in the usual manner at M. 

The instrument for measuring deflections is not shown in the 



59 

cut ; it consists of an accurately cut micrometer-screw of steel, 
having a pitch of 0.025 of an inch, working in a nut of the same 
material, mounted in a brass frame. This instrument is supported 
by a rod of considerable rigidity and of sufficient length, which is 
secured to the beam, C, close to the tension-rods, F, F, in such a 
manner that the micrometer is directly over the cross- head, in the 
same vertical plane with the test-piece, and very near and parallel 
with the axis of the large screw, K. The micrometer-screw is 
provided with a head which is divided into 250 equal' parts. Thus 
a rotary motion of one division produces an advance in the direc- 
tion of the axis of the micrometer-screw of 0.0001 of an inch. A 
scale divided into fortieths of an inch is fastened to the frame of 
the instrument, in close proximity to the head, and parallel to the 
axis of the screw ; it serves to mark the starting point, and indi- 
cates the number of revolutions made in taking a measurement 
with the screw. 

To insure accurate readings of the deflections, the principle of 
electric contact is here employed. Immediately underneath the 
micrometer-screw, on the cross-head, is placed an insulated metal- 
lic point, which is connected with one pole of one cell of a voltaic 
battery by means of an insulated conductor. The micrometer- 
screw is connected in a similar manner with the other pole. Thus, 
at the instant the screw touches the metallic point below it, con- 
nection is completed, and a current of electricity is established ; 
this fact is instantly indicated by the ringing of an electric bell 
placed in the circuit. By means of this instrument deflections of 
0.0001 of an inch can be measured. The capacity of the testing 
machine is 7,000 pounds. 

The test-pieces, size A, of the hot-rolled iron, and sizes A' and 
B' of the cold-rolled iron, were too heavy to be tested on the ma- 
chine just described, the distance between the supports being 
insufficient to permit breaking them down under the maximum 
power of the machine. 

The cold -rolled test-pieces, size B', were tested on the Fairbanks 
machine up to 7,000 pounds, on supports 52 inches apart, which was 
sufficient only to strain them slightly beyond the Elastic Limit, as 
will be seen on the curves. Sizes A and A' were also tested up to 
7,000 pounds on this machine to determine the Modulus of Elas- 
ticity.- 



60 

These large bars were finally broken down in the Tensile Test- 
ing Machine, to which a transverse testing attachment is fitted. 



DEFINITION OF TERMS. 



(1.) The Modulus of Elasticity has been defined as the ratio of 
the distorting force to the amount of distortion, whether the latter 
be produced by extension or compression, so long as the Elastic 
Limit is not exceeded. For tension or compression, we have, 
therefore : 

E =S ■ m 

The method of determining the Modulus of Elasticity by trans- 
verse stress is also based upon the above formula ; since a transverse 
stress necessarily produces a tensile and a compressive strain on 
opposite sides of the neutral surface of the bent bar ; this " neutral 
surface " is an unstrained section perpendicular to the distorting 
force at the point of its application, and passing through the centre 
of gravity of the cross- section of the unbent test-piece, or nearly 
so.* 

By means of an analysis which would be out of place here, \^ e 
find: 

Where 

E=the Modulus of Elasticity, 

P=load, 

D=the deflection due to P, 

L== " length between the supports, 

7T r 4 

I == " Moment of Inertia, which is equal to — - — , in round 

•4 

bars, r being the radius. 

* The neutral surface passes exactly through the centre of gravity of the 
cross-section of the bar, only when the material oilers the same resistance to 
compression as to tension and is perfectly homogeneous. 

f Wood's Ktsistance of Materials, pp. 105 and 113. 



61 

(2.) The Elastic Limit within which the above formula is ap- 
plicable is reached when the rate of deflection changes, becoming 
greater, in proportion to, increase of load, than at the beginning of 
the test. This point is not marked on the strain-diagram. 

The practical limit of elasticity as given in curves and records 
is generally considerably higher, and is taken at the point at which 
the permanent set becomes practically objectionable. This point 
may be found from the tables, but is more readily determined from 
the curves, where it is marked E. 

In fixing the Elastic Limit for the test-pieces here reported 
upon, 0.05 inch has been assumed to be the greatest allowable set 
in a bar 1 inch square and 22 inches long. 

(3.) The Modulus of Rupture, or the Modulus of Maximum 
Resistance, as determined by transverse stress, is defined to be 
the maximum strain upon a section of fibres one inch square 
most remote from the neutral surface, and on the side which 
first ruptures, if rupture occurs.* R, the Modulus of Maximum 
Resistance as given in the tables, is derived from the formula 

R=^ • (3) 

in which P, L, I and r are the same as in formula (2.) 

(4.) Transverse Resilience. Elastic and Ultimate Resiliences 
have already been defined as being a measure of the capacity of a 
material to resist shock within the Elastic Limit, or up to the 
point of rupture, and their respective values are equal to the 
amounts of energy expended, or work performed, in springing a 
piece without injuring it or in producing fracture. 

A true Modulus of Transverse Resilience cannot be obtained ex- 
cept by basing the calculations upon hypothesis, and making as- 
sumptions' which experiments will not always justify. In the tables 
and in the following discussion, therefore, the Resiliences given are 
those of a standard bar of the metal tested, one inch square and 22 
inches between the supports. This reduction of the Resiliences 
will answer quite well for purposes of comparisou, and may also be 

* "Wood's Eesistance of Materials, p. 156. 



62 

used as a basis for calculating the Resiliences of bars of any size of 
the same material. All the bars in this lot of test-pieces being too 
ductile to be broken, the Ultimate Resiliences could not be exactly 
determined, but are taken up to certain limits within those of rup- 
ture ; i. e., at the Elastic Limit and at deflections of two inches. 

The Transverse Resilience at any given deflection is readily 
found from the appended strain-diagrams, plotted from the re- 
duced figures. In these diagrams each inch of ordinate represents 
500 pounds resistance, and each inch of abscissa measures one-half 
inch of deflection. 

The formula is derived as follows : 

Let W=the Resilience, 

P m =the mean stress applied, 
0=the mean ordinate, 

S=the abscissa of the point to which W is to be calcula- 
ted, 
D— deflection at the same point, 

A=the area, in square inches, included between O, S and 
the curve. 

According to definition, 

W=P m D (4) 

From the scale of the curve, 

D=0.5 S 



and 
but 

hence 



P m =500 

o=A. 






substituting these values of D and P m in formula (4), we have 
W=500^+0.5S 



=250 A inch-pounds of work, 



or 



_2M)_ A=20.83 A foot-pounds. 
The latter is used in the tables, as it is the more common unit of 
work. 



63 

( 5 ) Reduction of Results, In order that the results of the tests 
of these bars of various sizes might be directly compared, they 
were all reduced to a common standard. That here adopted is the 
standard transverse test-piece of the Mechanical Laboratory of the 
Stevens Institute of Technology — a bar 1 inch square in section 
and 22 inches between supports. 

The formula of reduction is derived as follows : 

Let P ; =the actual load on the round bars tested, 

P'^the load which would produce the same strain on a 
round bar, 1 inch in diameter, 
P=this load reduced to the standard, 
c?=the diameter of the test-piece. 
Supposing the length of the test-piece to be that of the standard 
(22 inches), we have : 
P':P"::d 3 :i. 

••• p "4 • • («) 

Again, we have : 

P : P" : : 1 : 0.589, 
0.589 being the strength of a cylindrical beam when that of a cir- 
cumscribing square beam is taken as unity.* 

.-. P"=0.589 P, 
and by substituting above 

V 

¥= — _ 
0.589d s 

For any other length, L, of test-piece than the standard (22 

inches), we have : 

p=^x p ' 



.22 0.589ef 

The Reduction of Deflections of bars of lengths, other than 22 

inches, was effected by the aid of the proportion actual Deflection : 

reduced Deflection : : L : 22, which gives Reduced Deflection == 

22 

— X Actual Deflection, L being the length, in inches, of the bar.f 

L 

Plotting of the Curves. From the results obtained from formula 

(6), the accompanying strain -diagrams were plotted. 

* Wood's Eesistance of Materials, p. 182. 

f This formula of reduction is only approximately true. 



64 

Each inch on the horizontal scale corresponds to 0.5 inch deflec- 
tion, an,d each inch on the vertical scale represents 500 pounds of 
stress. 

The Carves of Sets which are drawn with the strain-diagrams 
show the amounts of permanent distortion for all loads. The 
horizontal distance between the initial ordinate and any point in 
the curve of sets measures the set, or permanent distortion pro- 
duced by the load indicated by the height of that point, and the 
horizontal distance between the curve of sets and the strain-dia- 
gram measures the amount of recoil or spring when the load is 
entirely removed. 



DETAILS OF TESTS. 

Nos. 1106A, 1107A and 1108A were all of hot-rolled iron, 2.54 
inches in diameter — rough; they were tested on the transverse attach- 
ment to the Tension Testing-Machine with a distance between the 
supports of 22 inches. The loads were applied in increments of 
1,000 pounds and the deflections were measured for every load, and 
are recorded in the tables. The sets were observed for each addi- 
tion of 2,000 pounds. 

No. iioSA. This test-piece deflected with a fair degree of reg- 
ularity within the Elastic Limit, passing that limit under a load of 
14,500 pounds, equivalent to 1,500 pounds on the standard bar; 
it then deflected more and more rapidly and with some irregularity 
(see curve of this number, Plate X), until the maximum load, 
25,000 pounds, — equivalent to 2,590 pounds on the standard bar — 
was reached with a deflection of 2.90 inches. Here the test w T as 
discontinued. 

The Modulus of Elasticity is 25,422,000, the Elastic Resilience 
is 10.31, and the Ultimate — at 2 inches deflection — is 339.74 foot- 
pounds. The Modulus of Maximum Resistance was 85,500. This 
bar showed no signs of rupture after the test. 

No. 1 107 A. This bar deflected quite regularly within the Elas- 
tic Limit, which it passed at a load of 14,000 pounds — 1,450 on 
the standard. It then deflected very regularly and reached its 



65 

maximum load, 26,500 pounds — equivalent to 2,745 pounds on 
the standard test-piece — at a deflection of 2.9 inches. Tire resist- 
ance then began to decrease ; with 3.6 inches deflection, it bore but 
25,200 — or 2,611 pounds of load reduced to standard. 

The Modulus of Elasticity is 25,659,000; that of Maximum 
Resistance is 90,600 pounds. The Elastic Resilience is 7.55, and 
at 2 inches deflection the Resilience amounts to 338.90 foot-pounds. 
No signs of rupture appeared after testing. 

No. 1108A. This test-piece deflected very regularly within the 
Elastic Limit. It passed the limit under a load of 14,500 pounds 
— 1,450 pounds standard — after which it deflected rapidly and 
regularly and reached its Maximum Resistance, 26,000 pounds — 
equivalent to 2,694 pounds on the standard test-piece — with a 
deflection of 2.8 inches. With a deflection of 3.39 inches it still 
carried 25,500 pounds — 2,642 pounds on the standard bar ; but 
here it suddenly yielded, carrying but 14,275 pounds — equivalent 
to 1,470 pounds of reduced load — at a deflection of 3.45 inches. 
The test was here discontinued. 

The Modulus of Elasticity is 26,146,000 ; that of Maximum 
Resistance is 88,890 pounds. The Elastic Resilience is 8.44, and 
the total Resilience at 2 inches deflection is 342.66 foot-pounds. 
This bar showed indications of rupture at the close of test. 

Nos. 1109A' 1110A' and 1111A' were of cold-rolled iron, 2x 

' . / lb 

inches in diameter ; they were tested like the preceding, except 
that the distance Jbetween supports was 33 inches. 

No. nogA'. This bar deflected regularly within the Elastic 
Limit, which it passed under a load of 18,000 pounds, equivalent 
to 2,165 on the reduced scale ; it then deflected more and more 
rapidly and with fair regularity until it reached its maximum load, 
23,000 pounds — equivalent to 4,040 pounds standard — with a de- 
flection of 2.30 inches. At a deflection of 2.38 inches the bar 
sustained 22,550 pounds — equivalent to 3,965 pounds on the stan- 
dard bar — having there suddenly weakened, (see curve No. 1109A', 
Plate X). 

The Modulus of Elasticity of this bar is 29,998,000 ; that of the 
Maximum Resistance is 133,480 pounds. The Elastic Resilience 
is 42.29 foot-pounds, and at a deflection of 2 inches the Resilience 

5 



66 

is 575.12 foot-pounds. No signs of rupture could be detected at 
the end of the test. 

No. nioA' behaved very similarly to the preceding test-piece 
while under stress. It passed its Elastic Limit under a load of 
18,000 pounds — equivalent to 3,165 pounds on the standard bar. 
It then deflected quite regularly and more and more rapidly, and 
reached its maximum load, 23, 200 pounds — equivalent to 4,080 
pounds standard — with a deflection of 2.27 inches ; it then lost 
strength, sustaining only 22,290 pounds — equivalent to 3,920 
pounds of reduced load — with a deflection of 2.38 inches. 

The Modulus of Elasticity is 28,195,000 ; that of Maximum 
Resistance is 134,640 pounds. The Elastic Resilience is the same 
as that of the preceding one — 42.19 foot-pounds ; at 2 inches 
deflection, the total Resilience is 573.49 foot-pounds. No visible 
rupture was found after the test. 

No. 1 1 1 1 A r . This test-piece deflected even more regularly within 
the Elastic Limit than did its two companion specimens, and it 
passed the latter point under the same load — 18,000 pounds, or 
3,165 pounds on the reduced scale. After passing the Elastic 
Limit, it deflected rapidly, but not quite as regularly as did 
the two preceding test-pieces. It reached the Maximum Stress, 
23,200 pounds, which is equivalent to 4,080 pounds of reduced 
load, at a deflection of 1.99 inches. The Modulus of Elasticity is 
30,843,000 ; that of Maximum Resistance is the same as that of 
the preceding test-piece, 134,640 pounds. The Elastic Resilience 
is 4.670 foot-pounds, which is slightly less than that of the pre- 
ceding ; at a deflection of 2 inches, the Resilience is 579.91 foot- 
pounds. No signs of rupture were visible after the test. 

No. ii28A' was cold-rolled and annealed iron, off the same bar 
as the other cold-rolled bars, marked A'. The distance between 
the supports was 22 inches, and the load was applied in increments 
of 1,000 pounds. This test-piece passed its Elastic Limit under a 
load of 15,380 pounds, which is equivalent to 1,800 on a standard 
bar. It then deflected with considerable irregularity (see curve 
No. 1128 A', Plate X), then still more regularly, and finally carried 
the maximum load, 24,500 pounds — equivalent to 2,870 pounds 
of reduced load — at a deflection of 2.56 inches, after which it 
weakened very rapidly, sustaining only 18,300 pounds, or 2,145 
pounds standard, at a deflection of 2.68 inches. 



67- 

The Modulus of Elasticity is 30,539,000 ; that of Maximum 
Resistance is 94,790 pounds. The Elastic Resilience is 11.25 foot- 
pounds, and at 2 inches the total Resilience is 394.31 foot-pounds. 
No signs of rupture appeared after the test. 

The test-pieces Nos. 1106B, 1107B and 1108B were hot-rolled 
iron, 2.08 inches in diameter. These bars were all tested on our 
Fairbanks transverse testing-machine, with a distance of 44 inches 
between the supports. The loads were applied in increments of 200 
pounds, and the deflections recorded for every load, as seen in the 
tables, where the actual as well as the reduced figures are given. 

No. 1 106B passed its Elastic Limit under a load of 3,630 pounds, 
equivalent to 1,375 pounds on the standard bar. It then deflected 
rapidly, but with some irregularity, until it reached its maximum — 
5,750 pounds, equivalent to 2,170 pounds standard — after having 
deflected 5.5 inches — equivalent to 2.75 inches with the standard 
bar. At a deflection of 6 inches — equivalent to 3 inches deflection 
of the standard test-piece — it still sustained the same load. Here 
the test was discontinued. 

The Modulus of Elasticity is 28,197,000, while that of Maxi- 
mum Resistance is 71,590 pounds. The Elastic Resilience is 9.74 
foot-pounds, and at 2 inches of deflection the total Resilience is 
282.49 foot-pounds. 

No. 1107B deflected somewhat irregularly within the Elastic 
Limit, which it passed under a load of 3,580 pounds — equivalent 
to 1,350 pounds on the standard bar. It then deflected rapidly 
and very regularly until the load became 4,000 pounds, when the 
bar suddenly stiffened, as is best shown by the offset in curve No. 
1107B, Plate XI. It gave a Maximum Resistance of 5,950 pounds, 
with a deflection of 8 inches ; this on a standard bar would be 
equivalent to 2,245 pounds and a deflection of 4 inches. The test 
was then discontinued. 

The Modulus of Elasticity is 27,592,000 ; that of Maximum 
Resistance is 74,080 pounds. The Elastic Resilience is 8.44 foot- 
pounds, and the total Resilience at a deflection of 2 inches is 286.00 
foot-pounds. No signs of rupture were discovered after the test. 

No. 1108B passed its Elastic Limit under the same load as did 
the preceding test-piece, 3,580 pounds, equivalent to 1,350 pounds 



68 

on the standard bar ; it then deflected rapidly and somewhat irreg- 
ularly, (see curve No. 1108B, Plate XI,) until it reached a Maxi- 
mum Resistance of 5,880 pounds at a deflection of 7 inches, which 
on the standard bar would be equivalent to a load of 2,220 pounds 
and a deflection of 3.5 inches. 

The Modulus of Elasticity is 28,404,000 ; the Modulus of Max- 
imum Resistance is 7l>,210 pounds. The Elastic Resilience of this 
test-piece is 8.59 foot-pounds, and the Resilience, at a deflection of 
2 inches, is 282.49 foot-pounds. No signs of rupture could be 
detected on the surface of the bar. 

Bars Nos. 1109B', 1110B' and HUB' were of cold-rolled iron 
shafting, 2 inches in diameter. These test-pieces were tested upon 
the Fairbanks transverse testing machine up to 7,000 pounds — the 
full capacity of the machine ; the distance between the supports 
was made 52 inches — the full length of the specimen. The load 
was applied in increments of 250 pounds, and the deflections were 
recorded as usual. 

No. nogB' was first tested with a distance of 44 inches between 
the supports, and increments of loads of 200 pounds up to 7,000 
pounds ; the supports were then put 52 inches apart, and the loads 
again applied and deflections measured as before. Thus these three 
test-pieces were strained considerably beyond their Elastic Limits, 
but not nearly to their Maximum Resistance. . They were finally 
tested on the altered tension machine ; the details of these tests are 
given in the tables. Curves Nos. 1109B / , 1110B' and 1111B', 
Plate XI, exhibit graphically the behavior of the specimens in both 
tests. The portions a 5, of the curves, are plotted from the results 
of the initial tests, and the dotted continuation, b c y is supposed to 
be the curve which would have been given if the tests could have 
been carried through without intermission, thus making smooth 
curves a b c, whereas the actual curves are a b b f , which have a 
sudden rise at 6, showing a considerable elevation of ultimate 
strength caused by their having been previously strained beyond 
the Elastic Limits. The curves a' b h' were obtained from the 
final tests. In the tables of comparative results the probable values 
deduced from the curves a b e will only be given ; but in the fol- 
lowing discussion the results of both will be stated and com- 
pared. 



69 

No. 1109B/ as represented by curve a b c, passed its Elastic 
Limit under the standardized loads,* 2,950 pounds, after which the 
deflections for equal increments of load increased gradually for 
some distance, then more and more rapidly, until the probable 
maximum resistance of 4,200 pounds was reached. As represented 
by curve a' b b', on the second test, it pass.ed its Elastic Limit 
under a load of 3,700 pounds, which is 750 pounds more than be- 
fore, and it reached its maximum strength at 4,350 pounds and a 
deflection of 2.35 inches. The Elastic Resiliences are 45.47 and 
40.08 foot-pounds, respectively ; whereas the Resiliences at 2 
inches deflection are, from curve a b c, 560.54, and from a' b b' 
628.03 foot-pounds. 

The Modulus of Elasticity of this bar is 27,896,000. The Mod- 
ulus of the probable Maximum Resistance is 136,000, while that 
obtained from final test is 143,500 pounds, showing an increase of 
7,500 pounds. 

No. moB', as represented by the curve a b c, passed its Elastic 
Limit under a load of 3,050 pounds, after which the deflections 
increased until the probable maximum was reached, at about 4,120 
pounds. On the curve a! b b' the Elastic Limit is noted at a load 
of 3,650 pounds, which is an increase over that of the initial test, 
of 600 pounds. It reached its Maximum Strength, 4,300 pounds, 
with a deflection of 2.41 inches. The Elastic Resiliences are, 
respectively, 54.00 and 36.48 foot-pounds ; while the Resiliences at 
2 inches are, respectively, 545.12 and 622.61 foot-pounds. 

The Modulus of Elasticity is 26,452,000; the Moduli of the 
probable Maximum Resistances, and of that obtained from the final 
test are, respectively, 135,200 and 142,100; the latter being the 
greater by 6,900 pounds. 

No. iiiiB' passes the Elastic Limit on the curve a b, at a load 
of 3,050 pounds, after which the curve runs very much like the 
preceding, reaching the probable Maximum of Resistance of 4,100. 
On the curve a' b b\ the Elastic Limit is passed under a load of 
3,850 pounds — 700 pounds higher than on the partial test. The 
Maximum Resistance at the final test was 4,310 pounds — 210 pounds 
more than at the previous test. The deflection for the maximum 

*For actual loads, consult the tables. 



70 

load was 2.11 inches, after which it suddenly lost strength, resisting 
only 3,862 pounds at a deflection of 2.27 inches. 

The Elastic Resiliences are, respectively, 52.87 and 48.12 foot- 
pounds. The Resiliences at 2 inches deflection are, respectively; 
550.75 and 644.69 foot-pounds. The Modulus of Elasticity is 
28,256,000, and the Moduli of Maximum Resistances are, respect- 
ively, 142,100 and 135,000 foot-pounds, the probable Modulus 
being 7,100 pounds below that obtained at the second test. 

No. 1128B', of cold-rolled iron and annealed, was 2 inches in 
diameter, and was tested at a distance of 38 inches between the 
supports. The load was applied by adding 500 pounds at a time 
up to 3,000 pounds, then by increments of 250 pounds. The 
deflections were noted as before. This test-piece passed its Elastic 
Limit under a load of 5,030 pounds, equivalent to 1,850 on the 
standard bar. It then deflected regularly, and reached its Maxi- 
mum Resistance, 7,000 pounds, at a deflection of 4.35 inches, which 
is equivalent to 2,570 pounds, and to a deflection of 2.52 inches 
for a standard bar. 

The Modulus of Elasticity is 27,463,000 ; that of Maximum 
Resistance is 84,670 pounds. The Elastic Resilience is 15.41 foot- 
pounds. At a deflection of 2 inches the Resilience is 354.74 foot- 
pounds. No sign of rupture appeared after the test was completed. 

Nos. 1106C, 1107C and 1108C of hot-rolled iron; Nos. 1109C 
1110C and 1111C of cold-rolled iron, and No. 1128C (C is 1.36 
and C Ij-q inches in diameter) were tested with a distance of 30 
inches between the supports. The stress was applied by increments 
of 100 pounds, and the deflections noted for every load; the sets 
were measured for each additional 300 pounds of stress. 

No. 1106C passed its Elastic Limit under a load of 1,410 pounds 
— equivalent to 1 ,300 pounds on the standard bar — after which it 
bent rapidly and pretty regularly until it reached its Maximum 
Resistance, 2,170 pounds, with a deflection of 2.58 inches when 
reduced to the standard. 

The Modulus of Elasticity of this bar is 28,143,000 ; that of 
Maximum Resistance is 65,900 pounds. The* Elastic Resilience is 
7.52 foot-pounds, and at a deflection of 2 inches of Resilience 
amounts to 265.56 foot-pounds. After the deflection of 3.5 inches 
— 2.58 on the standard — was reached, the test was discontinued. 



71 

No. 1107C passed its Elastic Limit under a load of 1,448 pou: ds, 
equivalent to 1,330 pounds of standardized load — after which it 
deflected rapidly but less regularly than the preceding bar, until it 
reached its Maximum Resistance of 2,440 pounds with a deflection 
of 2.6 inches, which, when reduced to the standard, is equivalent 
to 1,959 pounds of load and 1.91 inches of deflection. The test 
was continued until the deflection was 4 inches, at which the load 
was 2,185 pounds — equivalent to 2.93 inches deflection, and 1,964 
pounds of load per standard bar. 

The Modulus of Elasticity is 28,624,000, and that of Maximum 
Resistance is 64,990 pounds. The Elastic Resilience is 8.64 foot- 
pounds, and at a deflection of 2 inches the total Resilience is 
270.16 foot-pounds. 

No. 1108C. This bar deflected more regularly within the Elas- 
tic Limit than did its two companion test-pieces ; it passed the limit 
under a load of 1,468 pounds — equivalent to 1,350 pounds per stan- 
dard. It then deflected rapidly and uniformly, reaching its Maxi- 
mum Resistance, 2,125 pounds, with a deflection of 3 inches, which 
standardized, is equivalent to 1,956 pounds of stress and a deflec- 
tion of 2.19 inches. The resistance then decreased, and at a 
deflection of 3.5 inches it was only 2,060 pounds, or in reduced 
figures, 2.56 inches deflection and 1,896 pounds of stress. Here 
the test was discontinued. 

The Modulus of Elasticity is the same as that of the preceding 
bar — 28,624,000 — and the Modulus of Maximum Resistance is 
64,540 pounds. The Elastic Resilience is 9.56 foot-pounds; at a 
deflection of 2 inches the Resilience is 269.54 foot-pounds. 

The Maximum Resistances, and consequently the Resiliences, at 
2 inches deflection for the three preceding test-pieces are exceedingly 
low, compared with the other sizes. The maximum load was also 
reached with a less deflection than with the other bars of untreated 
iron. 

No. 1109c, of cold-rolled iron, deflected very regularly within 
the Elastic Limit, which it passed under a load of 2,392 pounds, 
equivalent to -2,450 pounds on the standard bar; it then deflected 
more and more rapidly and quite uniformly, until the Maximum 
Resistance, 3.400 pounds, was reached at a deflection of 3 inches — 
equivalent on the standard bar to 3,482 pounds of stress and 2.2 



72 

inches of deflection. With a deflection of 3.5 inches the load re- 
duced to 3,355 pounds — equivalent to 2.57 inches of deflection and 
3,436 pounds of stress on the standard. 

The Modulus of Elasticity is 26,625,000, and that of Maximum 
Resistance is 114,890 pounds. The Elastic Resilience is 26.45 
foot-pounds, and at a deflection of 2 inches the Resilience is 494.72 
foot-pounds. 

No. nioC passed its Elastic Limit under a load of 2,600 pounds, 
and then deflected more and more rapidly and with regularity, 
reaching its maximum load, 3,470 pounds, at a deflection of 3 
inches — equivalent to 3,553 pounds on the standard bar and a de- 
flection of 2.20 inches. The test was discontinued when the deflec- 
tion had reached 3.5 inches, the resistance having decreased to 
3,290 pounds — equivalent to 2.57 inches of deflection and a stress 
of 3,370 pounds when reduced to the standard. 

The Modulus of Elasticity is 25,655,000, and that of Maximum 
Resistance is 117,620 pounds. The Elastic Resilience is 32.97 foot- 
pounds, and at 2 inches of deflection the Resilience is 500.34 foot- 
pounds. 

No. iiiiC' was more irregular in its deflection within the Elas- 
tic Limit than its two companion specimens. It passed its Elastic 
Limit under a stress of 2,550 pounds, equivalent to 2,490 pounds 
on the standard bar; it then deflected very similarly to the two 
preceding bars, reaching its Maximum Resistance, 3,500 pounds, 
with a deflection of 3.5 inches — equivalent to 3,584 pounds of 
stress and 2.56 inches of deflection per reduced scale. 

The Modulus of Elasticity is 27,671,000, and that of Maximum 
Resistance is 118,390 pounds. The Elastic Resilience is 34.76 
foot-pounds, and at a deflection of 2 inches the Resilience is 503.46 
foot-pounds. The Elastic Limit and the Maximum Resistance, and 
consequently the Elastic Resilience as well as the Resilience at 2 
inches deflection for size C, will be found much lower than any ot 
the other cold-rolled bars; this may be due partly to the fact that 
the hot-rolled bars of size C were not as strong as the other sizes ; 
but it is perhaps due still more to the fact that the percentage of 
reduction by cold-rolling is least in size C. The percentages of 
reduction by cold-rolling run as follows: A, 4 per cent.; B, 3.85 
per cent.; C, 3.48 per cent.; D, 3.84 per cent.; and E, 6 per cent. 



No. 1128C was of cold-rolled and annealed iron, and was tested 
in all respects like the preceding bars. It deflected very uniformly 
within the Elastic Limit, which it passed under a stress of 1,844 
pounds — -equivalent to 1,900 pounds on the standard bar ; it then 
deflected more and more rapidly, and quite regularly, and reached 
its Maximum Resistance at a deflection of 4 inches, which, reduced 
to the standard, is equivalent to a load of 2,500 pounds and a de- 
flection of 2.93 inches. 

The Modulus of Elasticity is 27,188,000, and that of Maximum 
Resistance is 82,620 pounds. The Elastic Resilience is 19.00 foot- 
pounds, and at a deflection of 2 inches the Resilience is 352.90 
foot-pounds. 

It is remarkable that although the hot-rolled and the cold-rolled 
bars of size C are inferior, the cold-rolled and annealed bar of the 
same size should be superior in many of its qualities to the annealed 
bars of the other sizes. 

Nos. 1106D, 1107D and 1108D were of untreated iron ; the 
diameter of each was 1.04 inches, and the distance between the 
supports was made 22 inches. The stress was applied by kicre- 
ments of 40 pounds, and the deflections measured as before. The 
sets wergL measured for every 200 pounds, and the tests were 
tabulateu as before. 

No. 1106D passed its Elastic Limit under a load of 1,140 pounds 
— equivalent to 1,720 pounds on the standard test-piece ; it then 
deflected very irregularly, (see curve No. 1106D, Plate XIII) 
showing five distinct and almost complete cessations of molecular 
"flow" before reaching its Maximum Resistance — 1,620 pounds — 
equivalent to 2,455 pounds on the reduced scale, with a deflection 
of 4 inches. 

The Modulus of Elasticity is 25,782,000, and that of Maximum 
Resistance is 80,690 pounds. The Elastic Resilience is 14.37 foot- 
pounds, and at a deflection of 2 inches the total Resilience is 317.92 
foot-pounds. 

The sudden strengthening of this and of the next two bars at 
various stages of the test, so plainly exhibited by the curves, is 
not due to the method of testing, since these bars were not allowed 
to rest at any point, but were tested as continuously as all the 



74 , 

others, which show no such peculiarities ; the same must therefore 
be some peculiarity of structure in the material itself. 

No. 1107D. This bar deflected quite uniformly within the Elas- 
tic Limit, which it passed under a stress of 1,160 pounds— equiva- 
lent to 1,750 pounds per reduced scale. It then deflected rapidly 
and almost as irregularly as the preceding test-piece, showing simi- 
lar abrupt elevations in the strain-diagram due to the same cause. 
It reached its Maximum Resistance, 1,650 pounds — equivalent to 
2,490 pounds on the standard bar — at a deflection of 4 inches. 
Here the test was discontinued. 

The Modulus of Elasticity is 27,233,000, and that of Maximum 
Resistance is 82,180. The Elastic Resilience is 14.58 foot-pounds, 
and at a deflection of 2 inches the Resilience is 322.09 foot- 
pounds. 

No. 1108D deflected very regularly within the Elastic Limit, 
which it passed under the same load as did the preceding test- 
piece, viz., 1,160 pounds — equivalent to 1,750 pounds on the 
standard bar. It then deflected somewhat more uniformly than 
did the two preceding specimens, but still very irregularly, until it 
reached its Maximum Resistance, 1,700 pounds — equivalent to 
2,565 pounds on the reduced scale — with a deflection of 4 inches. 

The Modulus of Elasticity of this test-piece is 25,782,000, and 
that of Maximum Resistance is 84,670 pounds. The Elastic Resil- 
ience is 14.52 foot-pounds, and at a deflection of 2 inches the Re- 
silience is 326.56 foot-pounds. 

Nos. 1109D', 1110D' and 1111D' were of cold-rolled iron, 1 inch 
in diameter, and were tested under exactly the same conditions as 
were the three bars of which the tests have just been described. 

No. nogD' deflected very regularly within its Elastic Limit, 
which it passed under a load of 1,780 pounds — equivalent to 3,000 
pounds ger reduced scale. It then deflected more and more rapidly 
and pretty regularly, excepting that a rapid increase of resistance 
was observed just before reaching the maximum load. The latter, 
2,450 pounds — equivalent to 4,150 pounds of reduced load — was 
reached with a deflection of 2.13 inches, after which the strength 
decreased gradually, until at a deflection of 4 inches it carried only 
2,370 pounds — equivalent to 4,024 pounds on the standard bar. 



• 75 

The Modulus of Elasticity is 27,094,000; that of Maximum 
Resistance is 136,740 pounds. The Resilience at the Elastic 
Limit is 43.74 foot-pounds, and that at 2 inches deflection is 
571.15 foot-pounds. 

No. inoD' deflected quite regularly within the Elastic Limit, 
which it passed under a stress of 1,800 pounds — equivalent to 
3,056 pounds on the reduced scale — after which it deflected more 
and more rapidly, although not very regularly, showing some of 
the peculiarities of the untreated bars ; it reached its Maximum 
Resistance, 2,440 pounds — equivalent to 4,143 pounds on the 
standard bar — with a deflection of 2 inches. After this the re- 
sistance decreased, bearing only 2,350 pounds — equivalent to 3,990 
pounds on the standard — with a deflection of 4 inches. 

The Modulus of Elasticity is 27,163,000, and that of Maximum 
Resistance 136,690 pounds. The Elastic Resilience is 44.47 foot- 
pounds, and at a deflection of 2 inches the Resilience amounts to 
582.19 foot-pounds. 

No. iiiiD' deflected with considerable regularity within the 
Elastic Limit. It passed that point under a load of 1,800 pounds 
— equivalent to 3,056 pounds on the standard bar. It then 
deflected more and more rapidly, and reached its Maximum Re- 
sistance, 2,400 pounds — equivalent to 4,076 pounds on the reduced 
scale — with a deflection of 1.71 inches. After passing its maxi- 
mum it very gradully decreased in resistance, until, with a deflec- 
tion of 4 inches, it had reduced to 2,335 pounds — equivalent to 
3,977 pounds of reduced load. 

The Modulus of Elasticity of this bar is 27,094,000, and the 
Modulus of Maximum Resistance is 133,430 pounds. The Elastic 
Resilience is 47.22 foot-pounds, and at a deflection of 2 inches the 
Resilience is 576.46 foot-pounds. 

Nos. 1106E, 1107E and 1108E were test-pieces of hot-rolled iron, 
0.665 inch in diameter. They were tested with a distance between 
the supports of 22 inches. The stress was applied in increments 
of 20 pounds, and the deflection measured and recorded as before. 
The sets were observed and noted for every 200 pounds of load. 

No. no6E passed its Elastic Limit under a stress of 303 pounds 
— equivalent to 1,750 pounds on the standard bar — after which it 



76 

deflected very rapidly until its maximum, 380 pounds — equivalent 
to 2,194 pounds per reduced scale — was reached, it having deflec- 
ted 3.25 inches. Here the test was discontinued. 

The Modulus of Elasticity is 28,528,000, and that of Maximum 
Resistance is 72,390 pounds. The Elastic Resilience is 21.88 
foot-pounds ; the Resilience at 2 inches deflection is 298.13 foot- 
pounds. 

No. 1107E. This test-piece passed its Elastic Limit under a 
stress of 303 pounds — equivalent to 1,750 pounds on the standard 
bar. It then bent very rapidly and quite regularly until the 
Maximum Resistance, 380 pounds — equivalent to 2,194 pounds of 
reduced load — was reached with a deflection of 3.35 inches. Here 
the test was stopped. 

The Modulus of Elasticity is 28,705,000, and that of Maximum 
Resistance is 72,390 pounds. The Resilience at the Elastic Limit 
is 21.88 foot-pounds, and that at 2 inches deflection is 292.71 foot- 
pounds. 

No. 1108E passed its Elastic Limit under the same load as did 
the preceding test-piece, and deflected in a similar manner, reach- 
ing its Maximum Resistance, 380 pounds — equivalent to 2,194 
pounds on the standard bar — with a deflection of 3.5 inches, at 
which point the test was discontinued. 

The Modulus of Elasticity is 28,343,000, and the Modulus of 
Maximum Resistance is the same as in the two preceding cases — 
72,390 pounds. The Elastic Resilience is 20.41 foot-pounds, and 
at a deflection of 2 inches the Resilience is 294.59 foot-pounds. 

Nos. 1109E', 1110E' and 1111E' were test-pieces of cold-rolled 
iron, f inch in diameter. 

No. nogE' passed its Elastic Limit under a load of 410 pounds 
— equivalent to 2,850 pounds of reduced stress. Its deflections 
then very gradually, but not very rapidly, increased, until the load 
of 570 pounds — equivalent to 3,964 pounds — was reached; it 
then gave way quite rapidly, its resistance being a maximum at a 
deflection of 1.53 inches. The maximum load was 580 pounds — 
equivalent to 4,033 pounds per reduced scale. 

The Modulus of Elasticity is 27,443,000, and that of Maximum 
Resistance is 133,090 pounds. The Elastic Resilience is 55.80 foot- 



77 

pounds, and at a deflection of 2 inches the Resilience measured 
545.62 foot-pounds. 

No. inoE' had the same Elastic Limit as had the preceding test- 
piece ; it then deflected similarly, but more regularly, giving the 
same Maximum Resistance, which it reached with a deflection of 2 
inches. 

The Modulus of Elasticity is 27,094,000 ; the Modulus of 
Maximum Resistance is the same as in the preceding case. The 
Elastic Resilience is 56.99 foot-pounds ; the Resilience, at a deflec- 
tion of 2 inches, is 540.21 foot-pounds. 

No. iiiiE' passed the Elastic Limit under the same stress as 
did its companion test-pieces, after which it, however, deflected 
more rapidly and more uniformly, but reached the same Maximum 
Resistance at a deflection of 2 inches. 

The Moduli of Elasticity and of Maximum Resistance were the 
same as those of the preceding test-piece, viz., 27,094,000 and 133,- 
090 pounds respectively. The Elastic Resilience is 58.18 foot- 
pounds, and at a deflection of 2 inches the Resilience is 529.27 
foot-pounds. 

No. 1128E', of cold-rolled and annealed iron, was tested in the 
same manner as were the preceding test-pieces, of size E ; it passed its 
Elastic Limit under a load of 260 pounds — equivalent to 1,808 
pounds on the standard bar — after which the deflection increased 
more and more rapidly until the Maximum Resistance, 342 pounds, 
— equivalent to 2,378 pounds on the reduced scale — with a deflec- 
tion of 3.5 inches it still carried the same load, after which the 
resistance decreased. 

The Moduli of Elasticity and of Maximum Resistance are 
respectively 26,687,000 and 78,480 pounds. The Elastic Resili- 
ence is 24.75 foot-pounds, and at a deflection of 2 inches the 
Resilience amounts to 333.96 foot-pounds. 



78 



E/BSUMB. 



I.— HOT-ROLLED, OE UNTREATED IRON. 

In reviewing the results which have been discussed in the pre- 
ceding pages, and comparing the tables and curves, we find : 

(1.) That the average strength of the hot-rolled iron, when 
reduced to the standard bar, is about 2,300 pounds, which gives an 
average Modulus of Resistance of 76,000 pounds. From Table I 
of Comparative Results, we see that the largest bar has the greatest 
Modulus of Transverse Resistance, and that it does not decrease 
regularly with the diameter of the test-piece — size D (l^- inches 
diameter), having a very high Modulus of Resistance, only 5,800 
pounds less than that of size A. With the exception of size D, the « 
decrease of the Modulus of Resistance with the diminution of the 
diameters of the bar are very marked. In tension, the Modulus 
increased as the diameters decreased, but not in so marked a degree. 
The curious fact that the capacity of size D to resist transverse stress 
is above the average, while it falls below the average in resisting 
tensile strength is as probably due to differences in the iron as to 
differences in distribution of resisting power in the, section of the 
bar. With size C (If inches diameter) the reverse is the case. 

(2.) That the average Elastic Limit is 1,550 pounds, and that 
this approaches the Maximum Resistance as the diameters of the 
test-pieces decrease, as is best observed from the curves CC and 
C'C ', Plate XV, which approach each other more closely as they 
pass from A to E. 

(3.) That the Resiliences vary with the Elastic Limits and with 
the Maximum Resistances of the test-pieces; the Elastic Resili- 
ences being greatest with the smallest bars and the Resiliences at 
deflections of 2 inches increasing with the sizes of the test-pieces ; 
but without any regularity in either case. 

(4.) That the Moduli of Elasticity vary between 25,000,000 
and 29,000,000, and that they are independent of the diameters of 
the test-pieces. 



79 



II.— COLD-ROLLED IRON. 

From a study of all the records of tests of cold-rolled iron 
which were individually discussed in the preceding pages, we learn : 

(1.) That the Maximum Resistance of a cold-rolled bar of the 
standard size is 3,980 pounds — 1,665 pounds greater than that of 
the hot-rolled iron — giving a Modulus of 131,000 pounds — 55,100 
pounds greater than that of the latter. Except with size C (1 t 5 g 
inches diam.), there is no marked difference in the Moduli of Re- 
sistances for the different diameters, as is shown by the curve AA 
Plate XV. This may be partly due to the fact that the smaller 
sizes, except C, were reduced more by cold-rolling than were the 
larger ones. 

(2.) That the average Elastic Limit is 3,040 pounds — 1,490 
pounds greater, or nearly double, that of the hot-rolled iron. The 
fact observed in the untreated iron that the Elastic Limit ap- 
proaches the ultimate strength as the diameters decrease, is not 
true for the cold-rolled iron ; but it appears nevertheless to be 
more dependent upon the ultimate strength than is the case in 
tension. 

(3.) That the Resiliences, Elastic and Ultimate, are independent 
of the diameters of the test-pieces. The average Elastic Resilience 
is 45.2 foot-pounds, while that of hot-rolled iron is only 13.32 
foot-pounds. 

(4.) That the Moduli of Elasticity range between 25,000,000 
and 30,000,000, and are independent of the diameters of the bars 
tested. 

III.— COLD-ROLLED AND ANNEALED IRON. 

The results of these tests also show : 

That by annealing the cold-rolled iron it loses all its character- 
istic properties in a very marked degree, behaving under stress 
more like untreated than like cold-rolled iron. 

The Elastic Limit fand Maximum Resistance are only slightly 
higher than those of the untreated iron. This difference, however, 
is more marked under transverse stress than in tension. The ten- 
sile resistance of the annealed iron is but very little greater than 
that of the untreated iron. 



80 



GENERAL CONCLUSIONS. 



From a study of the accompanying strain-diagrams and the ap- 
pended tables, as well as from what has previously been stated, the 
following general conclusions may be readily drawn : 

(1.) The process of cold-rolling produces a very marked change 
in the physical properties of the iron thus treated : 

(a.) It increases the tenacity from 25 to 40 per cent., and the 
resistance to transverse stress from 50 to 80 per cent. 

(6.) It elevates the Elastic Limits under both tensile and trans- 
verse stresses, from 80 to 125 per cent. 

(c.) The Modulus of Elastic Resilience is elevated from 300 to 
400 per cent. The Elastic Resilience to transverse stress is aug- 
mented from 1 50 to 425 per cent. 

(2.) Cold-rolling also improves the metal in other respects : 

(a.) It gives the iron a smooth, bright surface, absolutely free 
from the scale of black oxyde unavoidably left when hot-rolled. 

(b.) It is made exactly to gauge, and for many purposes requires 
no further preparation. 

(e.) In working the metal the wear and tear of the tools are 
less than with hot-rolled iron, thus saving labor and expense in 
fitting. 

(d.) The cold-rolled iron resists stresses much more uniformly 
than does the untreated metal. Irregularities of resistance ex- 
hibited by the latter do not appear in the former ; this is more 
particularly true for transverse stress, as is shown by the smooth- 
ness of the strain-diagrams produced by the cold-rolled bars. 

(e.) This treatment of iron produces a very important improve- 
ment in uniformity of structure, the cold-rolled iron excelling 
common iron in its uniformity of density from surface to centre, 
as well as in its uniformity of strength from outside to the middle 
of the bar. 



81 

(3.) This great increase of strength, stiffness, Elasticity and Re- 
silience is obtained at the expense of some ductility, which dimin- 
ishes as the tenacity increases. The Modulus of Ultimate Resil- 
ience of the cold-rolled iron is, however, above 50 per cent, of 
that of the untreated iron. 

Cold-rolled iron thus greatly excels common iron in all cases 
where the metal is to sustain maximum loads without permanent 
set or distortion. 

(4.) We conclude, that as a material of construction, cold-rolled 
iron has many peculiar advantages ; that it is suitable for all con- 
structions not exposed to high temperatures ; that it is especially 
suitable for all purposes demanding a high Elastic Limit and 
great shock resisting power without permanent distortion ; that 
the process improves the metal throughout — its benefit, as has 
been seen, reaching the centre of the bar, and rendering the 
whole much more homogeneous and uniform than common iron — 
and that in many cases it may prove superior even to some steels 
as a material of construction. 

The tables of summaries will be found particularly convenient 
as exhibiting most concisely all data obtained. The table of 
working and breaking loads, Table L, page 88, will be of especial 
value for many cases of practical application. 

Very Respectfully, 

R. H. THURSTON. 



82 



TABLES 



AND 



tFINJLL* SUMMARIES OF COMPARABLE RESULTS. 



LOT No. 1. 

A— COLD-ROLLED IRON. 

All specimens of this Lot were tested without previous prepara- 
tion in the lathe. 



Lab. 
No. 


Orig-. 

inal 

Mark. 


Diam- 
eter, 
inches. 


Elastic 
Limit. 


Modulus 
per squa 

Original 
Section. 


of Bupture 
re inch of 

Fractured 
Section. 


Modulus 

of Eesil- 

ience. 


x, [ Per ct. 

Per *. -~ 
! of Ee- 

c ™ i duction 

Of * 

„ , - of area 

Exten -atPrac- 

slon - ture. 


1133 
1134 
1135 


1-66 
2-66 
3-66 


2 * 

n 


59,450 
59,450 
62,000 

60,300 


64,800 
66,500 
67.000 

66,100 


67,400 
72,700 
75,300 

71,800 


600 
1,672 
2,770 


1.15 ! 3.86 
2.75 8.62 
4.35 10.95 


Av'rage. 






1,681 
3,107 


2.75 
5.60 


7.81 


1140* 
1141* 


1-66 
2-66 
3-66 


2 

U 

u 


* 
57,500 66,400 

! 67,200 

57,500 I 67,200 


91,800 
83,500 
91,900 

89,067 

87,900 
96,200 
83,300 

89,133 


27.74 
19.88 


1142* 


7,136 


11.00 


26.88 

24.83 

23.21 
29.78 
17.81 


Av'rage. 




57,500 66,933 


' 




1147 
1148 
1149* 


1-66 
2-66 
3-66 


u 
(< 


1 
56,200 ! 67,500 
60,000 67,500 
56,200 68,500 


3,616 
4^710 
2,913 

4,163 


5.85 
7.35 
4.90 


Av'rage. 






57,467 


67,833 


6.60 


23.60 


1154 

1155* 

1156* 


1-66 
2-66 
3-66 


1 
U 

it 


58,709 
63,700 
58,700 


67,800 
68,500 
68,200 


100,900 
101,900 
101,400 


5,164 
4,909 
3,360 

5,164 


8.05 
7.45 
5.30 

8.05 

4.85 
3.75 
5.00 

4.53 


■32.77 

32.77 
32.77 


Av'rage. 






60,367 r 68,167 


101,400 


32.77 


1161 
1162 
1163 


1-66 
2-66 
3-66 


5 

8 
u 

ct 


63,800 
67,100 
60,600 

63,833 


73,800 
72,200 
75,500 

73,833 


106,800 3,566 

92,000 2,657 

104,800 3,670 


30.90 
19.81 
27.96 


Av'rage. 




101,200 3,298 


26.22 



All the numbers marked thus * broke outside of the initial marks. 



83 



B.— UNTREATED IRON. 



Lab. 


Origi- 
nal 
Mark. 


Diam- 
eter. 
Inches 


Elastic 
Limit. 


Modulus of Rupture 
per square inch of 


Modu- 
lus of 

Resili- 
ence. 


Percentage of 

Exten- Jedct'n 
• ot area at 
„ ' Fracture. 


No. 


Original 
Section. 


Fractured^ 
Section. 


1136* 
1137 

1138* 


•4-66 
5-66 
6-66 


9 9 
t< 
<( 


29,800 
26,200 
29,800 


46,900 
46,900 
46,400 


67,800 
74,700 
68,500 


8,777 

11,081 

7,710 

11,081 

8,232 
12,717 


20.55 
25.55 
18.20 


31.55 
37.85 
32.09 


Av'age 






28,600 


46,733 


70,333 


26.25 


33.83 


1143 
1144 
1145 


4-66 
5-66 
6-66 


9 i 


28,200 
28,200 


48,500 
48,900 
48,100 


69,000 
81,300 


19.25 
28,75 


29.63 
39.80 


Av'age 


1 


28,200 | 48,500 


75,150 


10,475 


24.00 


34.72 


1150* 
1151* 
1152* 


4-66 
5-66 
6-66 


If 
(( 


24,300 
24,300 
24,300 


50,300 
50,300 
50.300 


83,000 
80,000 
81,500 


9,272 

6,497 

10,141 


22.00 
15.65 
22.60 


39.68 
37.16 
38.31 


Av'age 


i 


24,300 j 50,300 


81,500 




38.37 


1157* 
1158* 
1159* 


4-66 
5-66 
6-66 


1 1 
(( 
(( 


26,100 
28,900 
28,100 


47,300 
47,300 
47,600 


81,500 
77,600 
79,900 


7,946 
9,882 
9,718 


21.75 
23.60 
25.30 


41.91 
38.97 
40.45 


Av'age 






27,700 


47,400 


79 667 






40.44 


1164* 

1165 

1166* 


4-66 
5-66 
6-66 


43 

<< 


29,200 50,100 
29,200 j 43,600 
29,200 1.50,800 


72,200 
69,900 
78,500 

73,533 


8,001 

8,761 

10,032 

8,761 


16.55 
19.35 
20.95 

19.35 


30.61 
37.66 
37.66 


Av'age 




29,200 1 48,167 


35.31 



*AU numbers marked thus * broke outside of the initial marks. 

C— COLD-ROLLED AND ANNEALED IRON. 





Origi- 
nal 
Mark. 


Diam- 
eter. 
Inches 


Elastic 
Limit. 


Modulus 


of Rupture 


Modu- 
lus of 
Resili- 
ence. 


Percentage of 


Lab. 
No. 


per squs 

Original 
Section. 


ire inch of 

Fractured 
Section. 


Exten- 
sion. 


Reduc'n 
of area 
at Frac- 
ture. 


1139* 
1146* 
1153 


X 

XII 


5* 

1 

5 

8 


31,400 
31,800 
31,600 
32,700 
33,600 


46,300 
49,600 
49,500 
50,900 

48,700 


75,400 
78.400 
86,900 
75,600 
76,100 


6,076 
5,619 
4,927 
5,857 

6,777 


14.25 
12.50 
9.50 
12.65 
15.80 


38.80 
36.78 
43.09 


1160 




32.77 


1167* 




36.00 









*A11 those test-pieces whose numbers are marked with an asterisk (*), broke 
outside of the scale, and therefore the extensions given in the table are not the 
ultimate extensions, and the Moduli of Resilience are only those due to the ex- 
tensions measured, and are not comparable. 



81 



LOT No. 2. 

All specimens #f this Lot were turned to their respective diame- 
ters from bars 2 inches in diameter. 

D— COLD-ROLLED IRON. 



Lab. 


Origi- 
nal 
Mark. 


Diam- 
eter. 
Inches 


Elastic 
Limit. 


Modulus of Kupture 
per square inch of 


Modulus 

ofEesil- 

ience. 


Percent 

Exten- 
sion. 


age of 
Eeduc- 


No. 


Original 
Section. 


Fractur'd 
Section. 


tion of 
area at 
frac're. 


1168* 




If 

l 


63,900 
56,600 
56,700 


66,900 
68,500 
60,600 


94,800 
95,500 
86,200 


3,877 
4,930 
3,794 


6.00 
7.65 
6.55 


29.44 


1169 




28.30 


1170 




31.12 

















E— UNTREATED IRON. 



1171 
1172 
1173* 



1^ 



30,900 
33,500 
26,000 



48,700 
49,500 
47,900 



83,100 
82.700 
78JOO 



14,120 

11,567 

8,997 



30.00 
25.70 
21.30 



41.38 
40.18 
39.14 



*All test-pieces whose numbers are marked with an asterisk (*), broke out- 
side of the scale, therefore the extensions given in the table opposite the re- 
spective numbers are not the ultimate extensions, and the Moduli of Kesilience 
are only those due to the measured extensions, and therefore neither are com- 
parable, but serve to show that the total extensions and ultimate Moduli of 
Kesilience for those particular specimens do not fall below the values given in 
the table. 



85 



LOT No. 3. 

All specimens of this Lot were turned to their respective diame- 
ters from bars 2 inches in diameter, 

F— COLD-ROLLED IRON. 











Modulus of Rup- 


Modulus of Resil- 


Percent- 


Lab. 


3 

5 


Elastic 
Limit. 


Modulus of 
Elasticity. 


ture per sq. in. of 


ience. 


age of 


Ko. 


i 








Reduc- 










Original Fractu'd 


Elastic. 


Ulti- 


Exten- 


tion of 




In 






Section. Section. 




mate. 


sion. 


frac. 


1105A 


7 

8 


54,900 


26,781,000 


65,850 


96,000 


109.76 


7200 


11.07 


31.35 


1105B 


4 


56,600 


27,829,000 


65,640 


93,000 


69.59 


5892.5 


9.00 


29.66 


1105 C 


8 


55,400 


25,743,000 


66,650 


90,600 


71.47 


5640 


9.22 


26.47 


1105D 


1 

5 


56,000 


28,989,000 


66,200 


91,600 


76.47 


5072.5 


8.14 


27.76 


1105E 


3 

8 


54,300 


22,261,000 


63,400 


99.000 


163.13 


4247.5 


7.29 


28.89 


1105F 


1 


50,900 


35,553,000 


64,660 


91,800 


51.16 


1945 


3.43 


29.60 



G— UNTREATED IRON. 



1104 A 
1104 B 
1104C 
1104D 
1104E 
1104 E 



8 


23,300 


4 


23,800 


* 


24.100 


1 


23,900 


X 


20,800 


1 

4 


22,400 



23,860,000 
25,679,000 
30,363,000 
30,150,000 
27,038,000 
33,317,000 



58,450* 


122,400* 


14.91 


12167.5* 


26.30 


49,330 


79,400 


18.77 


8607.5 


21.57 


50.520 


90,100 


18.09 


1087.5 


24.57 


50,980 


93,600 


26.33 


7757.5 


18.57 


52,540 


97,700 


26.25 


8500 


20.57 


42,980 


78,400 


23.52 


653.5 


16.93 



34.53 
37.85 
43.94 
40.42 

46.24 
47.28 



*The Moduli of Rupture of this test-piece, and in a less degree the Modulus 
of Resilience, have been unduly augmented by giving the test-piece an oppor- 
tunity to recover, after being strained greatly beyond its Elastic Limit. The 
Modulus of Rupture would very probably not have much exceeded 50,000 
pounds, and the Modulus of Resilience would undoubtedly have fallen below 
12,000 foot-pounds. 



86 



H— SUMMARY OF RESULTS. 



TRANSVERSE TESTS OP COLD-ROLLED SHAFTING. 



Results reduced to Standard ; bar 1 inch sq. and 22 inches long. 





Diam. 

in 
inches 


Elasticity. 


Resilience 
in foot-pounds. 


Modulus 
of Maxi- 
mum Re- 
sistance. 


Maxi- 
mum 
Load. 

4,040 
4,080 
4,030 

4,050 

4,200 
4,120 
4,100 

4,140 

3,482 
3,569 
,3,584 


Deflection 


Lab. 
No. 


Limit, 
lbs. 


Modulus. 


Elastic. 


When 
D=2 

inches. 


for 
Maxi- 
mum 
Load. 


1109A / 
1110A' 
1111A' 


2 ? 


3,165 
3,165 
3,165 


29,998,000 
28,195,000 
30,843,000 


42.19 
42.19 
40.67 

41.68 


575.12 
573.49 
679.91 

576.17 


133,480 
134,640 
134,640 

134,250 

136,000 
135,200 
135,000 


2.30 
2.27 
1.99 


Av'age. 


•»••«» 


3,165 


29,678,700 


2.19 


1109B / 
1110B / 
1111B' 


2 

u 
a 


2,950 
3,050 
3,050 


27,896,000 
26,452,000 
28,256,000 


45.47 
54.00 

52.87 


560.54 
545.12 
550.75 




Av'age. 




3,017 

2,450 
2,600 
2.550 


27,535,000 

26,625,000 
25,655,000 
27,671,000 

26,650,300 


50.78 

26.45 
32.97 
34.76 

31.39 


552.14 

494.72 
500.34 
503.46 


135,400 




1109C 
1110C / 
1111C 


it 

U 


114,890 
117,620 
118,390 


2.20 
2.56 
2.56 


Av'age. 




2,530 


499.50 


116,970 

136,740 
136,690 
133,430 

135,620 

133,090 
133,090 
183,090 


3,545 

4,160 
4,143 
4,076 

4,126 

4,033 
4,033 
4,038 

4,033 


2.44 


1109D' 
1110D' 
1111D' 


1 

a 

tt 


3,000 
3,056 
3,056 


27,094,000 
27,163,000 
27,094,000 


43.74 
44.47 

47.22 

45.14 


571.15 

582.19 
576.46 


2.13 

2 

1.71 


Av'age. 




3,037 

2,850 
2,850 
2,850 

2,850 


27,117,C00 

27,443,000 
27,094,000 
27,094,000 

27,210,300 


576.60 


1.95 


1109E' 
1110E' 
1111E' 


f 

u 

u 


55.80 
56.99 
58.18 


545.62 
540.21 
529.27 

538.40 


1.53 
2.00 
2.00 


Av'age. 




56 99 


133,090 


1.84 











D=Deflection in inches. 



87 



I— SUMMARY OF RESULTS. 

TRANSVERSE TESTS OF HOT-ROLLED SHAFTING. 

Results reduced to Standard ; bar 1 inch sq., 22 inches long. 





Diam- 
eter 
of bar. 
Inches 


Elasticity. 


Resilience 
in foot-pounds. 


Modulus 
of Maxi- 
mum 
Resist- 
ance. 


Maxi- 
mum 
Load. 


Deflect'n 


Lab. 
No. 


Limit. 
Po'nds 


Modulus. 


Elastic 


When 
*D=2" 


under 

maxim'm 

load. 

Inches. 


11 06 A 
1107A 
1108A 


2.54 
it 


1,500 
1,450 
1,500 


25,422,000 
25,659,000 
26,146,000 


10.31 
7.55 
8.44 


339.74 
338.90 
342.66 


85,470 
90,600 
88,890 


2,590 
2,745 
2,690 

2,675 

2,170 

2,245 
2,220 


2.66 

2.87 
2.80 


Av'rage. 


1,487 


25,742,300 


8.77 


340.43 


88,320 


2.78 




2.08 

u 
a 




1106B 
1107B 
1108B 


1,375 
1,350 
1,350 

1,358 


28,197,000 
27,592,000 
28,404,000 

28,064,000 


9.74 
8.44 
8.59 


282.49 
286.00 
282.49 


71,590 
74,080 
73,210 


3.00 
4.00 
3.5 


Av'rage. 




8.92 


283.66 


72,960 


2,212 


3.5 






1106C 
1107C 
1108C 


1.36 

Ct 

u 


1,300 
1,330 
1,350 


28,143,000 

28,624,000 
28,624,000 


7.52 
8.64 
9.56 


265.56 
270.16 
269.54 


65,900 
64,990 
64,540 


1,975 
1,959 
1,934 

1,956 


fi"2.68* 

1.91 
2.19 


Av'rage. 




1,327 


28,130,300 


8,57 


268.42 

317.92 
322.09 
326.56 


65,143 


2.23 


1106D 
1107D 
1108D 


1.04 

u 


1,720 
1,720 
1,750 


25,782,000 
27,233,000 
25,782,000 


14.37 
14.58 
14.52 


80,690 

82,180 
84,670 


2,455 

2,490 
2,565 


4 
4 

4 


Av'rage. 




1,740 


26,265,700 


14.49 


322.19 


82,513 


2,503 


4 


1106E 
1107E 
1108E 


0.665 

u 
u 


1,750 
1,750 
1,750 


-28,528,000 
28,705,000 
28,343,000 


21.88 
21.88 
20.41 


298.13 
,292.71 
294.59 


72,390 
72,390 
72,390 


2,194 
2,194 
2,194 

2,194 


3.25 
3.75 
3.5 


Av'rage. 




1,750 


28,525,300 


21.39 


295 14 1 


72,390 


3.5 













D=Deflection in inehes. 

K— SUMMARY OF RESULTS. 

TRANSVERSE TESTS OF COLD-ROLLED AND ANNEALED 

SHAFTING. 

Results reduced to Standard / bar 1 inch sg. , 22 inches long. 



Lab 


Diam. 
of Bar. 
Inches. 


Elasticity. 


Resilience 
in foot-pounds. 


Modulus of 

Maximum 

Resistance. 


Maxi- 
mum 
Load. 


Deflec- 
tion 

under 


No. 


Limit. 


Modulus. 


Elastic. 


"When 
D=2". 


maxi- 
mum 
load. 


1128A / 
1128B' 
1128C / 
1128D' 
1128E' 


9 i 
2 

1 

f 


1,800 
1,850 
1,900 
1,700 
1,808 


30,539,000 
27,463,000 
27,188,000 
25,845,000 
26,687,000 


11.25 
15.41 
19.00 
15.58 
24.75 J 


394.31 
354.74 
352.90 
319.17 
333.96 


94,790 
84,670 
82,620 
77,030 
78,480 


2,870 
2,570 
2,503 
2,334 

2,378 1 


2.56 

2.52 

2.93 

3 

4 



88 



m 
P 
< 
O 

y— i 
Ph 

<: 

t— i 
M 

o 



p 

Eh 




89 



ABSTRACT OF A REPORT 



ON 



TESTS OF COLD-ROLLED IRON 



MADE IN THE 



yVuTOQR/PHIC l^ECOFJDIJNQ fEgTINQ ^MACHINE. 




Testing Machine for Torsion. 

The machine employed in testing by torsional stress is known as 
the Autographic Kecording Testing Machine. It is shown in the 
accompanying engraving, as built and used in the Mechanical 
Laboratory of the Stevens Institute of Technology. 

It consists of two strong cast iron wrenches, facing each other, 
with a space of 1J inches between their jaws. They rotate on in- 
dependent journals, placed in the same line in the frames, AA; the 



90 

latter are bolted to a heavy bed-plate, which gives it the required 
stability. One of the wrenches is provided with an arm, 4.5 feet 
in length, at the lower end of which is attached a heavy weight, 
B; the other wrench has keyed to it a worm-wheel, M } engaging 
with the worm, L, which is set in motion by means of a crank. 
In this manner a very slow and quite uniform motion can be ob- 
tained. 

Both wrenches are provided with lathe-centres directly opposite 
each other and in the common axis of rotation. The specimen to 
be tested is placed upon the lathe- centres, which hold it in line 
while it is being secured in the jaws of the wrenches by means of 
steel wedges inserted from opposite sides. 

On the shaft of the wrench carrying the worm-wheel there is 
fastened a brass drum, G> which rotates with it, while to the other 
wrench is fastened a pencil-holder which allows the point of the 
pencil to move on the surface of the drum and is guided by the 
stationary curve, F } of brass, in such a manner that its position on 
the drum indicates the number of foot-pounds of moment exerted 
by the arm and weight, at any instant. 

Supposing a test-piece to be placed in the machine, the operator 
turns the crank, X, with a uniform velocity which gives a slow 
and a very steady motion to the wrench connected with the worm- 
wheel, which is transmitted through the test-piece to the wrench 
carrying the weighted arm. The latter is moved by the force 
transmitted through the test-piece through an arc which is a 
measure of the resistance to torsion offered by the test-piece, and is 
recorded simultaneously with the angle of torsion by the pencil up- 
on a diagram-sheet fastened .upon the drum for the purpose. 

The drum is of such a diameter that the circumference is 36 
inches, which, when divided into tenths, make 360 divisions, each 
of which is representative of one degree. The guide-curve is a 
curve of sines, which insures the position of the pencil on the 
drum always such that it marks an ordinate proportional to the 
moment of the arm and weight at every instant during the test. 

In the machine employed in the Mechanical Laboratory of the 
Stevens Institute of Technology, each inch of ordinate denotes 100 
foot-pounds of moment to have been transmitted through the test- 
piece, and each inch of abscissa indicates 10 degrees of torsion. 



91 

The friction of the machine is not recorded by the machine, but is 
added in calculating the results given in the tables. 

By means of this machine the metal tested is compelled to tell 
its own story and to give a permanent and graphical representation 
of its strength, elasticity, and every other quality which is brought 
into play during its test, and to exhibit the characteristic peculi- 
arities. 



DEFINITIONS AND EXPLANATIONS. 

Before passing to the discussion of the results -of the torsion 
tests themselves, it is necessary, in order to avoid misunderstand- 
ing, to define some of the more important terms, and to explain 
the methods by which the results given in Table M and to 
which data reference is frequently made in the discussions, were 
derived. 

1. The Modulus of Torsional Elasticity is the ratio of the dis- 
torting force to the amount of angular distortion which it produces, 
in a test-piece of which the length, the polar Moment of Inertia 
and the lever-arm of the applied force are each unity ; thus 

G =w < 3 ) 

Where 

G=Modulus of Torsional Elasticity, 
P— the applied force, 
L= length of test-piece, 
A=length of arm of P, 
0= angle of distortion produced by P, 
Ip— the polar Moment of Inertia, 



tl r 4 



, r being the radius of the test-piece. 



2 
And 7Z=3.1416. 

It must be remembered that in calculating the Moduli of Elas- 
ticity, P should always be taken well within the Elastic Limit. 

f Wood's Resistance of Materials, new edition, p. 206. 



92 

2. Resilience. The actual Torsional Resiliences, both Elastic 
and Ultimate, are given in the tables also. The Torsional Resil- 
ience is calculated by means of the formula, 

w_^ M L F 
V ~ R R 

which is derived as follows: 

Let Wr=the required Resilience, in foot-pounds, 

A=area in square inches included in the diagram up to 

the point of rupture, 

L=length of the base line in inches, 

M— the number of foot-pounds of moment represented by 

each inch of ordinate, supposing no friction, and 

R=radius of the drum in inches, we have 

A 

Y= j-=mean ordinate of diagram, 

P=Y M=value of mean ordinate, in foot-pounds, or pounds 
applied at distance of one foot from the axis of the 
jaws of the machine, which is the mean force exerted 
to rupture the test-piece ; 

T 

S— --~=distance moved through, in feet, by pencil, and since 

the pencil point is at a distance equal to the radius of 
the drum from the axis, the distance through which 
the mean force acts is 
(5-=radius of drum in feet): one foot : : \~= distance through jL 

X \J, ' 12 which mean force acts. J J? 

Therefore, still supposing no friction, the work done will be the 
product of the mean force into the distance through which it acts, 
and, 



R L ±C R 

The friction F, of the journal, previously referred to, assists 
this mean force, and is taken as acting at a distance of one foot 

from the ax?s ; it therefore acts through the same distance -^, and 

■p T 

other work is therefore expended equal to —^ 



93 

so that the total work performed is 

w AM FL 
W_ R x R 

The values of the Elastic Resilience, or the work expended in 
straining the material to its Elastic Limit, are determined in the 
same manner as those for the Ultimate Resilience. To find the 
Resilience for the Elastic Limit, the area a, of the initial portion 
of the diagram up to the Limit of Elasticity is measured, as also 
the abscissa I, corresponding to that point which when substituted 
in the formula above given, M, F and R remaining the same, we 
have the following : 

m f 

Resilience within the Elastic Limit = a ^ -\- I =■ 

3. Moduli of Torsional Resistance* The Moduli of Resist- 
ance, Proof and Maximum, as given in Table R, are represented 
in foot-pounds of Moment, i. e., in pounds of stress acting upon a 
lever-arm one foot long. 

M 
The Proof Modulus, A(= j^ ), represents the number of foot- 
pounds of stress required to strain a round bar, whose diameter (D) 

is unity,f up to its Elastic Limit. 

M' 

The Maximum Modulus, A' (= j~), is the greatest resistance, in 

foot-pounds, offered by the same bar while being ruptured. The 
ultimate resistance, or the resistance at the point of breaking, is 
not always a maximum. 

The Modulus of Elastic Stiffness, A K ( = wzfi)> i s & e moment in 

foot-pounds necessary to twist a Specimen of the given material, 
whose length (L) and diameter (D) are both unity, through an an- 
gle of one degree. 



*The above Moduli of Torsional Resistance are calculated according to Ran- 
kine; Machinery and Mill "Work, p. 501. 

f The inch is here taken as the unit of measure. 



94 

4. Ductility by Torsion. The relative ductility by torsion is 
given in the table under the heads "# K Final/' and " Ratio of Ex- 
tension, Ultimate.' 7 The former is the number of degrees of tor- 
sion, and the latter the extension of an external fibre at the point 
of rupture. 

The extension is that of an external fibre of the metal, origin- 
ally lying parallel with the axis, and usually exceeds in value that 
obtained by tension. It is calculated for the standard test-piece, 
whose length is one inch, and diameter 0.625 inch, by means of 
the formula : 



S= Vl+ A2 X0.0O002974775— 1 
in which S is the extension and A the total angle of torsion. 



DISCUSSION OF RESULTS OF TESTS BY TORSION. 

All the test-pieces were cut from round bars 1J-. in. diameter and 
dressed to the standard size in the workshop of the Mechanical 
Laboratory of the Stevens Institute of Technology. Twelve speci- 
mens are here reported upon ; 4 of the untreated iron, 6 of cold- 
rolled iron and 2 were cold-rolled and annealed iron. In the bar 
from which Nos. 1547B arid 1548B were cut, the process of cold- 
rolling was carried farther than in the others. 

Untreated Iron. 

The average Modulus of Resistance at the Elastic Limit is 381.8 
foot-pounds, and the Maximum is 932.93 foot-pounds of Moment. 
The average Elastic Resilience is 0.898, and the Ultimate Resil- 
ience is 733.13 foot-pounds of work. Excepting specimen No. 
1219, the Moduli of Elasticity are over 20,000,000, which is very 
high for torsion. The Modulus of Elastic Stiffness is also very 
high, the average being 1151.49 foot-pounds of Moment. The 
extension of the external fibre varies between 30 and 80 per cent. 
The strain-diagrams Nos. 1218, 1219, 1546A and 1547A, on 
Plate XYI, show graphically the behavior of these specimens 
under torsional stress. 



95 

The high elastic stiffness ; the smoothness with which the curves 
turn on passing the elastic limit ; their regularity of rise ; their 
altitude and their high torsional angles, show the metal to be an 
excellent material even as it leaves the common mill. It is stiff 
and strong, yet ductile, and is both uniform in quality and homo- 
geneous in structure. 

No. 1218, for example, gives one of the most perfect 
strain-diagrams that is to be found among the hundreds preserved 
in the portfolios of the Mechanical Laboratory of the Stevens In- 
stitute of Technology. It may be taken as a typical diagram for 
the finest quality of merchant bar-iron. 

Nos. 1219, 1546A and 1547A are seen to be a trifle more 
fibrous, as is shown by the slight depression of the line after pass- 
ing the Elastic Limit E, and somewhat less ductile, but they are 
also very excellent specimens of hot-rolled iron. 

Cold-Rolled Iron. 

The high Elastic Limit and Ultimate Stiffness, which is one of 
the most prominent features of cold-rolled iron, is as well marked 
in torsion as in tension and in transverse resistance. The Proof 
Moment is nearly double that of the untreated iron. The average 
Proof Modulus of Nos. 1203C, 1207C, 1547 A and 1547B is 
699.30 footpounds; that of Nos. 1548 A and 1548B is higher 
still, it being 922.15 foot-pounds of Moment. The average Modu- 
lus of Ultimate Strength of the former is 1035.55, and of the 
latter it is 1094.67 foot-pounds of Moment. The difference in 
Ultimate Strength is not so great as in the Elastic Limit. The 
average ductility of the external fibre is 20.17 per cent. Nos. 
1203C and 1548B are exceptionally low in ductility ; the former 
showed a flaw very plainly near the fracture, which reduced its 
strength and elastic stiffness. 

The average Elastic Resilience is 3.49 foot-pounds of work, 
nearly four times that of the untreated iron. The Ultimate Resil- 
ience is 561.12 foot-pounds of work. 

The Moduli of Elasticity and Elastic Stiffness are not quite as 
high as in the untreated iron. 



96 

Cold-Rolled and Annealed Iron. 

Annealing the cold-rolled iron reduces it very nearly to the state 
of the untreated iron in its properties to resist torsional as well as 
other stresses, but leaves the material more homogeneous as to 
strain. This is shown by the smoothness of the curves, Nos. 1804 
A and 1808A, which do not exhibit the counterflexure generally 
observed in strain-diagrams produced by specimens of untreated 
iron. No. 1804A retains the characteristics conferred upon it by 
cold-rolling, sufficiently to show plainly its origin. 

The Peculiar Action of Cold-Rolling. — Earlier 

Experiments. 

The writer had, as early as the year 1873, obtained, for his own 
satisfaction, a set of test-pieces of cold-rolled iron which were 
tested in the Autographic Testing Machine. The strain-diagrams 
were described, and a facsimile printed in a paper read before the 
American Society of Civil Engineers, in April, 1874, as follows : 

" No. 85 is a singular illustration of the effects of what is prob- 
ably a peculiar modification of internal strain. It seems to have 
no characteristics in common with any other metal examined. Its 
diagram would seem to show a perfect homogeneousness as to 
strain, and a remarkable deficiency of homogeneit} 7 in structure. 
It begins to exhibit the indications of an Elastic Limit at a, under 
a torsional movement of 110 foot-pounds, or an apparent tensile 
stress of 33,000 pounds per square inch, and then rises at once by 
a beautifully regular curve, to very nearly its maximum at 18°, 
and 176 foot-pounds. The maximum is finally reached at 130 
and thence the line slowly falls until fracture takes place at 195 
The maximum resistance seems to be very exactly 60,000 pounds 
to the square inch. Its maximum elongation for exterior fibres is 
about 0.23. The Resilience taken at the Elastic Limit is far higher 
than with common iron, and it is seen that this metal, in many 
respects, may compete with steel. Its elasticity is seen to remain 
constant wherever taken. 

" This singular specimen was a piece of ' cold-rolled ? iron. It 
is probably really far from homogeneous as to strain, but its arti- 
ficially produced strains are symmetrically distributed about its 



c 

3 

C 



97 

axis, and being rendered perfectly uniform throughout each of the 
concentric cylinders into which it may be conceived to be divided, 
the effect, so far as this test, or so far as its application as shafting, 
for example, is concerned, is that of perfect homogeneousness. 

" The apparently great deficiency of homogeneousness in struct- 
ure is readily explained by an examination of the pieces after 
fracture ; they are fibrous, and have a grain as threadlike as oak ; 
their condition is precisely what is shown by the diagram, and 
the metal itself is as anomalous as its curve." 

It was by these strain-diagrams, and at the time here referred 
to, that the real character of the peculiar and important change 
produced by cold-rolling was first discovered, and shown to be a 
remarkable elevation of the original elastic limit of the material. 

The elaborate series of investigations described in the report of 
which this is a partial abstract, have fully confirmed the deductions 
then made by the writer, and it is here shown for the first time that 
the exaltation of the primitive elastic limit by strain may be carried 
to such an extent as to make it equal to eighty per cent, and more, of 
the breaking load, a proportion which is not obtainable by any other 
process known to the writer. This fact has as much interest and 
importance when viewed from the scientific as from the practical 
side. 

In the strain-diagrams of Nos. 1548 A and 1548B, the modifi- 
cation produced in the cold-rolling mill is most strikingly shown. 
The stiffuess indicated by the steepness of the initial line rising to E, 
the height of the elastic limit — which is seen to approximate closely 
to the maximum resistance of the piece — and the increased strength 
of the iron, are apparent to the least observing eye. The ductility 
is seen to be somewhat reduced, but still remains available for all 
ordinary applications, and is greater than that of some hot- 
rolled iron which finds a ready market and has a high reputation. 

These diagrams not only exhibit the facts just given with perfect 
distinctness, but also show that the final rolling cannot be done at a 
high temperature if the improvement sought is to be made thor- 
oughly satisfactory and permanent. The study and measurement 
of these diagrams will probably prove more instructive and satis- 
factory to the majority of readers than the examination of the 
tabulated figures. 



98 



GENERAL CONCLUSIONS. 

From a study of the accompanying strain-diagrams and the ap- 
pended tables, as well as from what has previously been stated, the 
following general conclusions, already drawn, are fully corrobor- 
ated. 

(1.) The process of cold-rolling produces a very marked change 
in the physical properties of the iron thus treated. 

(a.) It increases the tenacity from 25 to 40 per cent., and the 
resistance to transverse stress from 50 to 80 per cent. 

(5.) It elevates the Elastic Limit under torsional as well as ten- 
sile and transverse stresses, from 80 to 125 per cent. 

(<?.) The Modulus of Elastic Resilience is elevated from 300 to 
400 per cent. The Elastic Resilience to transverse stress is aug- 
mented from 150 to 425 per cent. 

(2.) Cold-rolling also improves the metal in other respects : 

(a.) It gives the iron a smooth, bright surface, absolutely free 
Irom the scale of black oxyde unavoidably left when hot-rolled. 

(b.) It is made exactly to gauge and for many purposes requires 
no further preparation. 

(c.) In working the metal, the wear and tear of the tools are 
less than with hot-rolled iron, thus saving labor and expense in 
fitting. 

(d.) The cold-rolled iron resists stresses much more uniformly 
than does the untreated metal. Irregularities of resistance ex- 
hibited by the latter do not appear in the former ; this is more 
particularly true for transverse stress, as is shown by the smooth- 
ness of the strain-diagrams produced by the cold-rolled bars. 

(e.) This treatment of iron produces a very important improve- 
ment in uniformity of structure, the cold-rolled iron excelling 
common iron in its uniformity in density from surface to centre, 
as well as in its uniformity of strength from outside to the middle 
of the bar. 



99 

(3.) This great increase of strength, stiffness, Elasticity and Resil- 
ience is obtained at the expense of some ductility, which dimin- 
ishes as the tenacity increases. The Modulus of Ultimate Resil- 
ience of the cold-rolled iron is, however, above 50 per cent, of 
that of the untreated iron. 

Cold-rolled iron thus greatly excels common iron in all cases 
where the metal is to sustain maximum loads without permanent 
set or distortion. 

Comparing the Autographic Strain-diagrams, we see evidence : 

(1.) That the curves exhibit the same peculiarities that were there 
also observed when testing these metals by transverse stress, and by 
tension. The diagrams of the cold-rolled iron, after the Elastic 
Limit is passed, gradually falls into a horizontal line ; while those 
of the untreated metal turn abruptly and generally show a counter- 
flexure in the curve, just beyond the Elastic Limit. 

(2.) That the diagrams of the annealed cold-rolled iron still re- 
tain some of the characteristics of those of the unannealed. 

(3.) That the result of the treatment of the metal is the elevation 
of the Elastic Limit more or less nearly to the limit of strength ob- 
served at final rupture and the change of the method of passing 
the Elastic Limit, making that change far less abrupt, and giving 
a smoother and more symmetrical curve than that noted on the 
strain-diagrams of the hot-rolled metal. 

Very Respectfully, 

R. H. THURSTON. 



100 



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Cold-Rolled 

and Annealed 

Iron. 



101 



ABSTRACT OF A REPORT 



ON 



COLD-ROLLED FINGER-BARS, 

FOR MOWING MACHINES. 



In the preceding pages I have reported in full upon a very ex- 
tensive and complete series of tests of Cold-Rolled Shafting and 
the iron from which it is made. 

The conclusions there arrived at in reference to the beneficial 
effects of the process of cold-rolling, as practiced at the American 
Iron Works of Jones & Laughlins, Pittsburgh, Pa., are general, 
and would seem to apply equally well to other forms of iron 
similarly treated. 

To determine whether this is true with regard to finger bars, as 
made at the American Iron Works, and to compare the cold-rolled 
iron finger-bars with those of steel made in the ordinary way, was 
the object of a series of tests, of which the following is a brief ab- 
stract : 

Tables N and O are summaries of results obtained by tension 
and transverse stress respectively, by studying which the great su- 
periority of the cold-rolled iron, in strength and ultimate stiffness, 
is seen at a glance. The process being carried further, the differ- 
ence is even more marked than in the cold-rolled shafting. 

The Modulus of Rupture is nearly double, and the Elastic Lim- 
it is more than three times that of the untreated iron ; the Modu- 
lus of Elastic Resilience is nearly tenfold. Ductility is reduced, 
but the Ultimate Resilience does not suffer in the same ratio. In 
tension it is a full third of that of the untreated iron, and 
under transverse stress it falls but very slightly below the latter 
in Ultimate Resilience. This metal is therefore peculiarly well 



102 

adapted for finger-bars, which, generally, are only called upon to 
overcome transverse resistance. 

In Table P is given a summary of the results of tests of eight fin- 
ger-bars by transverse stress. The untreated bars were f inch thick ; 
to make them directly comparable the results were reduced to those 
for a bar of the same dimensions as the cold-rolled bars. Compar- 
ing the reduced figures with those of the tests of cold-rolled bars the 
great superiority of the latter is at once evident. Even in direct 
comparison with the untreated finger-bars, which are 50 per cent, 
heavier than the cold-rolled, the latter surpass the former. The 
Elastic Resilience is nearly three times as great, and the Ultimate 
Resilience is also considerably higher. The untreated bars reach 
the Elastic Limit with a deflection of 1 inch, whereas the cold- 
rolled bars can be bent 2.75 inches before any appreciable set oc- 
curs. 

Manufacturers of reaping and mowing machines are well aware 
of the fact that for finger-bars a material of great strength and 
high elasticity is required. Cold-rolled iron is, therefore, much 
better adapted for the purpose than is untreated iron. 



COMPARISON BETWEEN COLD-ROLLED IRON AND 
STEEL FINGER-BARS. 

The great Strength, Elasticity and Ultimate Stiffness of cold- 
rolled iron, as shown by the numerous tests already made, and 
particularly the great regularity with which it yields under stress, 
justifies the conclusion that for many purposes it may be used, with 
advantage, in place of steel. It is inferred that in consequence of 
the peculiar character of its resisting qualities, cold-rolled iron is 
especially adapted for the most important members of harvesting 
machines. 

To determine the exact relative value of cold-rolled iron and 
steel finger-bars, by direct comparison, a somewhat extended series 
of tests were made — a summary of the results of which is found 
in Table Q. 



103 

From the table it is seen that the cold-rolled iron bars are from 
fifteen to twenty- five per cent, stronger than those of steel. The 
Resilience is also much higher. To break the cold-rolled bars it 
was necessary to bend them back and forth, 14 inches each way 
many times ; one of the bars was bent 10 inches each way 23 
times before it ruptured. The permanent sets for large deflections 
is much less with the cold-rolled iron than with the steel bars. 
(See Table Q under the head of Permanent Sets.) 

In addition to the above, the cold-rolled iron finger-bars exhibit 
a regularity of product and a smoothness of finish, which is great- 
ly in their favor. The work of fitting is also much more easily 
performed upon the cold-rolled iron than upon the steel bars. 

Tables R and S are here appended as giving for comparison 
the results of a series of independent supplementary tests of 
cold-rolled and untreated irons which may be useful for further 
comparison. 

In Conclusion, it may be said that cold-rolled iron finger-bars 
are well calculated to take the place of those made of steel, rolled 
in the ordinary manner, and that many other parts of the working 
mechanism, as well as the framework of harvesting machines, 
might, with advantage, be replaced by cold-rolled iron, thereby se- 
curing what is very desirable in such machines — a combination of 
maximum strength with minimum weight. 

Very Respectfully, 

H. R. THURSTON. 



104 



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